Need advice for engaging dry plate. [Archive] - Large Format Photography Forum

Pere Casals

3-Mar-2017, 17:35

Last six months I've been reading all I found about emulsion making and dry plate coating.

For the moment I've ordered Colloida P gelatin, Silver nitrate, KBr, Amonium bromide, Thymol, Erythrosine, and Pinacyanol, some arrived yet.

>> I concluded that I've to drop around 25ml of fresh emulsion on each 8x10 glass, this will be 0.5mm of fresh emulsion over the plate, then it may end in 0.05 after dryed. Is this right?

>> Also I'd like to know if somebody has practical experience by using a good and fast emulsion recipe and dye sensitization, and what dyes proportions. I concluded that I have to go to amonium emulsions if Pinacyanol sensitization is to be employed. Something better than TLF 1/2?

>> I'd like to know about dye combinations to obtain faster panchromatic emulsions...

>> I'm buiding a cabinet to mature the plates with controlled temperature.

>> I'm thinking in using an Airless paint sprayer to coat the glasses inside a box at some 35ºC, to avoid gelification inside the sprayer, can this be viable? I'm thinking in a "paint flow" of 100ml/min so it would take 15s to throw the guessed 25ml spread on the 8x10 glass...

koraks

4-Mar-2017, 01:57

Robert Brazile

4-Mar-2017, 05:32

I've been working with dry plate emulsions since taking the workshop at the Eastman Museum a while back. I actually have some of the same questions you have, because I've concentrated on mastering the various steps and learning about exposure and development before moving further into working with speed, ortho/pan sensitivity, and other coating methods.

That is, I'm still doing the basic color blind recipe and pouring plates by hand, and while it's really not difficult, it's taken me a while to get the hang of it. While you can certainly jump in where you're thinking, it seems to me you're multiplying a bunch of variables that will make it a bit more difficult to master, whereas a methodical, step-by-step approach might get you to the same place faster in the end.

That having been said, experimenting with erythrosine should be simple enough; my plan is simply to get the other stuff nailed down first.

By way of example, my most recent plate (color blind, hand poured, VERY slow):

https://c1.staticflickr.com/1/287/32868962032_c655299fe2_z.jpg (https://flic.kr/p/S5w2gW)
I4P-041, Two portraits, #2 (https://flic.kr/p/S5w2gW) by Robert Brazile (https://www.flickr.com/photos/rbrazile/), on Flickr

Robert

jnantz

4-Mar-2017, 09:24

nice work robert !

===

pere

go to the light farm, buy denise's book
there is a lot there.

you might be looking for trouble with a paint sprayer..
sounds like it will be a complete mess
coating by hand or coating rod/blade/pour/brush &c is the way to go
i've coated glass by hand/pour and brush it really isn't as hard as it seems.

DHodson

4-Mar-2017, 10:29

mdarnton

4-Mar-2017, 14:56

I don't have emulsion experience, but I do spray a lot of varnish through an airbrush, and I think you do not want to spray.
1/ It takes skill--lots of skill.
2/ 25ml in 15 seconds is way too fast--you will have a mess, and runs
3/ In order to coat full thickness right up to the edges, you are going to have to spray beyond the edges, and I will guess that you would lose half your emulsion coating the background support beyond the glass to make sure the glass is fully coated right to the edges.

I'll guess if spraying was the easier and better way, everyone would have figured that out by now.

Pere Casals

4-Mar-2017, 17:26

No experience here, but I've read quite a bit about emulsion making as well. I never saw a clue that dyes do much to enhance sensitivity; they only affect spectral response. Controlled ripening of the emulsion and the rate at which AgNO3 is added seems to be the key to higher sensitivity, as it affects grain size.

Also, the TLF recipes are tried and tested. Even if they are too slow for your taste, why not try to walk before you try to run a marathon?

Spraying seems like a messy way to coat plates with a great potential for unevenness and emulsion all over your coating area. What's wrong with pouring?

A basic dye sensitization may increase speed by 2x to white light, not sensitized emulsion is only blue sensitive (well, if using some KI it has some green sensitivity) as sensitized emulsion also takes green and red photons, before sensitization those photons were lost.

Of course, the ripening is key...

OK, I'll start pouring...

Pere Casals

4-Mar-2017, 17:43

I've been working with dry plate emulsions since taking the workshop at the Eastman Museum a while back. I actually have some of the same questions you have, because I've concentrated on mastering the various steps and learning about exposure and development before moving further into working with speed, ortho/pan sensitivity, and other coating methods.

That is, I'm still doing the basic color blind recipe and pouring plates by hand, and while it's really not difficult, it's taken me a while to get the hang of it. While you can certainly jump in where you're thinking, it seems to me you're multiplying a bunch of variables that will make it a bit more difficult to master, whereas a methodical, step-by-step approach might get you to the same place faster in the end.

That having been said, experimenting with erythrosine should be simple enough; my plan is simply to get the other stuff nailed down first.

By way of example, my most recent plate (color blind, hand poured, VERY slow):

Robert

Great result !!!

I'm just to follow your way: step by step. I'm near prepared to make first batch of emulsion, and then like you, I'll try to improve the emulsion.

It looks that erythrosine can be added in the B part before mixing, after washing with Thymol, or after coating by bathing the plates.

If added in the beginning it is not wased out later, well... it is washed but the erythrosine tied to chrystals remains, so no problem.

Just I was asking to prepare next step.

Great portraits!!! it has the antique look of a blue filter, of course, anyway I see a great result, very nice !

Pere Casals

4-Mar-2017, 17:56

Another vote for Denise's book - The Light Farm: Handmade Silver Gelatin Emulsions. It's well written and a great resource (available from Blurb though her website)

http://thelightfarm.com/

I don't have any experience with a sprayer but I'm wondering how you'd manage air bubbles in the emulsion. I'm just starting out with glass (4x5) but there's a section in her book on coating glass negatives and I'm in the process of putting together the coating station she describes. So far it's been pretty straightforward and will let me coat a bunch of negatives at once.

For the moment I've read all that's in the TLF site, and also I was planning to buy the book, also I was considering "PHOTOGRAPHIC EMULSION MAKING, COATING AND TESTING" BOOK & DVD'S BY RON MOWREY, as a ISO 40 panchromatic emulsion is described. I guess I need both...

I don't have emulsion experience, but I do spray a lot of varnish through an airbrush, and I think you do not want to spray.
1/ It takes skill--lots of skill.
2/ 25ml in 15 seconds is way too fast--you will have a mess, and runs
3/ In order to coat full thickness right up to the edges, you are going to have to spray beyond the edges, and I will guess that you would lose half your emulsion coating the background support beyond the glass to make sure the glass is fully coated right to the edges.

I'll guess if spraying was the easier and better way, everyone would have figured that out by now.

OK, I'll try pouring, and then the coating station described by Denise.

DHodson

4-Mar-2017, 18:48

It's nice that you can read the book on the Blurb site if you want to have a look at the section on coating glass negatives (P46).

Pere Casals

5-Mar-2017, 04:52

It's nice that you can read the book on the Blurb site if you want to have a look at the section on coating glass negatives (P46).

Yes, really nice, still it is a book to have at home. I guess that coating station it's all one can ever need. Upon your tip I've read it again, and now I think it's the way to go.

IMHO the TLF 2 emulsion is just the place to start, but I feel the emulsion is something that it may be improved a lot in the future.

Robert Brazile

5-Mar-2017, 05:50

Thanks for the nice comments, John, Pere Casals.

I should say that I recommend Denise's book as well; I found it to be a nice supplement to the materials from the Eastman workshop, particularly with respect to some practical alternatives for coating and examples of the results gained from tweaking. Plus she's planning a second volume to come.

That having been said, I thoroughly enjoyed the time spent with Mark and Nick at Eastman, and there's nothing like hands-on work with someone at your elbow to give guidance for making rapid progress, plus the fun of learning with the other participants, some of whom have become good friends. I've signed up for the intermediate class they're doing this summer as well, which should get into some of the topics being discussed here (improved speed, perhaps ortho). It will be a bit of a reunion for my class also, which is a real win for me.

A plate from yesterday (need a better model, but this one works cheap):

https://c1.staticflickr.com/4/3881/32436232853_a231e9dd50_z.jpg (https://flic.kr/p/RqhaY2)
BP-010, One light + dish (https://flic.kr/p/RqhaY2) by Robert Brazile (https://www.flickr.com/photos/rbrazile/), on Flickr

Robert

Robert Brazile

5-Mar-2017, 06:15

Oh, also meant to say that I endorse the idea of building a drying cabinet. In the interest of getting started quickly, you can just put them on a rack in a large cardboard box (provided of course that the corners and seams are well taped) and that will work well enough with an overnight wait. But I have learned that one key to good results is to arrange things so that you progress through the steps with efficiency -- i.e., minimal messing around -- and that this is greatly aided by having things laid out in advance (i.e., mise en place) and set up so you can move the plates through the various steps without having to stop and do anything else, such as opening and closing boxes, fussing with the plates already in the rack, etc. Otherwise you will (well, at least, I will/did) have avoidable mishaps.

I find everything works best if you can move in a slow, steady, controlled fashion, especially during the pour. In my case, for example, I discovered that I do a much better job of pouring if I have a) good (safe) light on the action, and b) do it over a large tray with a bit of water in it so I can avoid worrying about spillage. Once I did the latter, in fact, I stopped spilling as much off the edges because I could concentrate on what I was doing. Pour enough on the plate so the mass moves easily to the edges/corners without having to tilt it much, and it happens much more cleanly and smoothly, which just the slightest tilting of the plate required. Then pour it off from the corner, and rock it back to pour a little off the opposite corner to get the mass of (rapidly cooling) emulsion more evenly centered. A little rocking to move the still-wet emulsion around the plate evenly is nice, but not absolutely required. Then put it down on your leveled drying table (piece of granite or marble, larger means more plate capacity, which helps) with the edge of the plate off the edge of the table -- it may stick a bit from the poured-off emulsion on the back of the plate, so you'll want an edge to grab.

Once I've done 4 or 5 4x5s, the first in the series are usually set enough to put in the drying box. At the moment, I'm using a granite counter cut-off salvaged from a stone and tile place, about 1.5" thick, 6" wide and 24" long. Once filled, I pull the oldest one off the far end, move each plate down one spot, and make a place for the newest one at the near end. That way I figure there's a sort of gradient of heat from one end to the other, and it's worked well enough for me. Although the granite piece is thick enough that it seems to stay cold enough just fine without such considerations.

Best of luck with your learning -- I'd recommend jumping right in. I spent a long time after the workshop overthinking the process and trying to acquire a lot of equipment...too long, really, needlessly wasted a lot of time.

Once I got up the nerve to get going, though, I found that I was generally able to overcome most obstacles on the fly with stuff I had around the house, and it taught me a lot about what was really important to getting good results. Nothing like experience to teach you...

Robert

Pere Casals

5-Mar-2017, 10:05

Oh, also meant to say that I endorse the idea of building a drying cabinet...

Robert

Thanks for detailing your workflow, this information is very encouraging to me in order go straight to mix and coat. Today I coated a glass with gelatin only, to get some practice while waiting for the silver nitrate to arrive.

Also I've tested dust control, I use a cheap Honeywell HAP-16200E and it works perfect, I was using it for scanning but I wanted to know if it was also enough for coating. I discovered that it removes all dust in air of a 8m2 room in some 10 min, but it is also important to wear clothes that are not prone to emit dust.

I feel that adding erythrosine will be an easy improvement to have ortho, and still the convenience of working with safe light. I'm thinking to use the pinacyanol in a sensitizing bath after coating, in this way the plate can be coated under safe light, and later sensitized to red in total darkness. But first is making the first coating !!!!!

Thanks again for sharing your workflow.

jnantz

5-Mar-2017, 10:19

make sure your level slab is COLD
i didn't do this when i started out, and i
wasted a lot of effort teaching myself about
binding agents / sub layers which are not needed.
the cold stone sets the gelatin from the emulsion on the plate ..

good luck !

Pere Casals

5-Mar-2017, 13:38

Nodda Duma

5-Mar-2017, 14:18

Go look through the emulsion section of the APUG forum. Lot of good info there.

I've been doing this for a while now and have the process down. I use the basic recipe on unblinkingeye.com. Very rewarding. You'll want to figure out how to test for ISO speed of the emulsion. I do this, and generated an EV / exposure conversion chart in MS Excel for the emulsion's ISO so I can use my iphone light meter app out in the field. I print the chart on a piece of paper and take it with me. So if I meter EV 11, then I just look at my sheet to see what exposure for the f/# I want to use. In general, the difference in spectral response between the emulsion and phone camera can be corrected in the darkroom.

The attached photo is of a 16"x20" silver gelatin print enlarged from a 4"x5" plate. It hangs on our living room wall. The photog at work got wind of what I was doing, so now there's one hanging up in a hallway there along with a short blurb on the process. Every so often someone stops me and says it's pretty cool.

https://uploads.tapatalk-cdn.com/20170305/2d87b3e1d8935e40aba699b5f0445493.jpg

Btw, I divvy up and store the emulsion in cheese crocks in my beer fridge prior to coating. I stay so busy that I don't get to use the emulsion right away. It keeps for several months if the equipment is sanitized (no preservatives added).

I'll reiterate about the cold slab. Make sure it's level! I use a machinist's bubble level. You'll know the emulsion is set because there will be a subtle "wrinkling" or texture to the emulsion surface when you view the reflection of your safelight off the plate surface. When the emulsion hasn't yet set, it's smooth as glass. When you see this texture you can move it off the slab. Should only take a few minutes to set...depends on how diluted the gelatin is (avoid over-dilution by keeping the washing water as cold as possible).

I use a 10cc syringe to apply the emulsion to the plate. Works well for me.

Finally, only other advice is don't skimp on prepping your plates. Clean the glass so that water sheets off the glass rather than beading up. I use a sponge with rottenstone and dish soap to scrub both sides. I have to be extra diligent since I cut my own plates from larger surplus thin Schott borosilicate plates that I bought for cheap.

Pere Casals

5-Mar-2017, 15:15

Go look through the emulsion section of the APUG forum. Lot of good info there.

I've been doing this for a while now and have the process down. I use the basic recipe on unblinkingeye.com. Very rewarding. You'll want to figure out how to test for ISO speed of the emulsion. I do this, and generated an EV / exposure conversion chart in MS Excel for the emulsion's ISO so I can use my iphone light meter app out in the field. I print the chart on a piece of paper and take it with me. So if I meter EV 11, then I just look at my sheet to see what exposure for the f/# I want to use. In general, the difference in spectral response between the emulsion and phone camera can be corrected in the darkroom.

The attached photo is of a 16"x20" silver gelatin print enlarged from a 4"x5" plate. It hangs on our living room wall. The photog at work got wind of what I was doing, so now there's one hanging up in a hallway there along with a short blurb on the process. Every so often someone stops me and says it's pretty cool.

https://uploads.tapatalk-cdn.com/20170305/2d87b3e1d8935e40aba699b5f0445493.jpg

Btw, I divvy up and store the emulsion in in my beer fridge prior to coating. I stay so busy that I don't get to use the emulsion right away. It keeps for several months if the equipment is sanitized (no preservatives added).

I'll reiterate about the cold slab. Make sure it's level! I use a machinist's bubble level. You'll know the emulsion is set because there will be a subtle "wrinkling" or texture to the emulsion surface when you view the reflection of your safelight off the plate surface. When the emulsion hasn't yet set, it's smooth as glass. When you see this texture you can move it off the slab. Should only take a few minutes to set...depends on how diluted the gelatin is (avoid over-dilution by keeping the washing water as cold as possible).

I use a 10cc syringe to apply the emulsion to the plate. Works well for me.

Your image cannot be seen, anyway I visited your Flickr.

Thanks for the advice, I was also considering unblinkingeye recipe, good to know it is very rewarding. I'll remember the workflow details you mention, I found new practical advices I was not well aware.

For the speed calibration I was to follow the BTZS guidelines, I guess that at the end it's what you used. Thanks for the information, this encourages me to go forward, thanks !

Nodda Duma

5-Mar-2017, 15:30

Pere Casals

5-Mar-2017, 16:56

Wierd about the photo..shows up fine for me. Modern technology...

Anyhow, to test ISO I created several exposures against a black & white target (construction paper) so I could see response to shadows and highlights. I metered against the B & W subject as a reference, then developed in my favorite developer noting which exposure looked best. Once I had the "best" exposure, I backed out the ISO based on calculations available in the public domain. Very subjective yet scientific in all the right places.

Not sure this is the method you describe, but it works for me. My latest batch was ISO 0.25 because I didn't ripen it as much. Ok tho because I planned for a lot of landscape photos.

Your method is way straight, a simple bracketing may determine a personal ISO that's perfectly operative. This is also the way I think I'll use first. Later I plan to plot the "Lux·Second vs Density" graphs.

I envision making faster emulsions panchro in the future, and mixing fast with slow emulsions (perhaps the slower one in a layer under the faster) to get wide latitude, so at that point I would need to use the charts as described in the Beyond The Zone System book. But first, let's start with the basics !!!

The unblinkingeye recipe has a digestion times table related to speeds, I ask my self what ISO can be achieved with that recipe and proper digestion...

Fr. Mark

5-Mar-2017, 17:44

The 35 C spraying sounds interesting, but impractical. That's nearly core body temperature. Sauna? How do you get plates to set up?
Another thing about using sensitizing dyes is that you get into a regime where you start to need automation or IR night vision gear v. rapidly that way as ordinary LED or other common safelights aren't safe any more. They can over power ortho film like Ektascan B/RA, too.

I look forward to seeing more work done this way. Eventually, I want to join y'all in making emulsions. On a certain level, it doesn't make sense on another level, that kind of control of the process is really cool and there may be emulsion types that we want that can't be had from commercial sources, too.

Pere Casals

6-Mar-2017, 01:35

Another thing about using sensitizing dyes is that you get into a regime where you start to need automation or IR night vision gear v. rapidly that way as ordinary LED or other common safelights aren't safe any more. They can over power ortho film like Ektascan B/RA, too.

You can use sensitizing dyes and still you can see with safe light, if sensitizing Orthochromatic or Orthopanchromatic.

For Panchromatic plates there is a trick, you make the plates under safe light, and later you perform a sensitizing bath (Pinacyanol + Pinaverdol dyes), this time in darkrness.

You also can store the blue sensitive only plates during weeks, and the day before usage you can do the sensitizing bath, then you can decide to even sensitize infrared (with Cryptocyanine), and also you can decide to use an extra amount of amonia, in that way (hypersensitization) you can even have 4x the original speed but you have to expose and develop in few days to pervent excessive fog. This is what I concluded from readings, and it's what I would like to try.

The 35 C spraying sounds interesting, but impractical. That's nearly core body temperature. Sauna? How do you get plates to set up?
Another thing about using sensitizing dyes is that you get into a regime where you start to need automation or IR night vision gear v. rapidly that way as ordinary LED or other common safelights aren't safe any more. They can over power ortho film like Ektascan B/RA, too.

I look forward to seeing more work done this way. Eventually, I want to join y'all in making emulsions. On a certain level, it doesn't make sense on another level, that kind of control of the process is really cool and there may be emulsion types that we want that can't be had from commercial sources, too.

The spraying system was just an idea, by now I think it is a wrong path, anyway I was thinking to make a coating station inside a sort of box with the right temp inside to prevent gelification inside the sprayer, but I repeat, form previous posts of helping people, now I see the coating process as very straight, and no need to do it in a weird way, as you also suggest.

And yes... a lot of fun may be predicted :)

Like you I think making emulsion/plates has to be very rewarding in happiness terms !!!!!

minh0204

18-Jan-2018, 12:20

Pere, how's the emulsion making effort going?

Pere Casals

18-Jan-2018, 12:41

Pere, how's the emulsion making effort going?

Nice !!!!

This is my kit:

https://www.flickr.com/photos/125592977@N05/33551104771/in/dateposted-public/

https://c1.staticflickr.com/3/2886/33551104771_fca82e99bc_b.jpg

I got this $40 cheap new magnetic stirrer:

https://c1.staticflickr.com/3/2812/33270857213_3967e3036e_b.jpg

The magnetic stirrer it's really very convenient, it helps to automate very well the process.

I'm obtaining ISO 2 emulsion, for now I've been using my dry plates mostly to "print on glass" and obtaining big glass slides rather than to shot.

Until now I've made 3 emulsion batches only, but all worked very well, I'm building a drying cabinet with an HEPA filter, and I'm close to obtain flawless plates with no dust at all. Also my coating skills have been improving a lot.

I've not done more because I've several projects in course like a 810 enlarger, with dry plates I made enough to see viability, an soon I'll make another push to target some ISO 50 speed and to make a first try with Lumiere autochromes https://en.wikipedia.org/wiki/Autochrome_Lumi%C3%A8re

I'm fascinated by autochromes... in the future I'll shot BW dry plates and autochromes. It's awesome, but autochromes are made from potatos !!!!

Robert Brazile

19-Jan-2018, 06:24

I, too, am fascinated with autochromes, and the progress that Jon Hilty is making is inspiring. But as for me, I have a long way to go before I'm ready to tackle that, still want to improve my dry plate techniques first. Took the intermediate workshop at Eastman and learned a bit more. They now teach pouring cold, rather than heating the plates, and I find it to work much better, unless your pouring room in the basement is itself cold, in which case it works terribly. In that case, a bit of mild warming is helpful.

But we learned a bit about sensitization, both for speed and for color. I've done a bit of the former, via sulfur-sensitization, and doubled the speed of the plates. Steigmann's solution is next, followed probably by getting to erythrosine for ortho...finally.

It's great fun.

Robert

Pere Casals

19-Jan-2018, 06:54

followed probably by getting to erythrosine for ortho...finally.

Robert, the erythrosine addition is straight, you can use it in your next batch if you want, pretty straight, it just can be added at the beginning of the precipitation, in this way it has twice the effect (Mowrey told) than if it is used later. When you later wash the emulsion the sentitization it's not lost, because the erythrosine actually doing the job it is bonded to the silver halide and it remains, so throw some drops of 2% erythrosin (1gr in 50ml ethanol) in the salted gelatin... and it does the trick.

Erythrosine is cheap and safe, as it can be food grade, http://www.thelightfarm.com/cgi-bin/htmlgen.py?content=18Jan2012

You can use the dose told here http://www.thelightfarm.com/cgi-bin/htmltutgen.py?content=07Sep2013

Still I've not tried pinacyanol sensitization, but...:

If panchro wanted, when your ortho plates are dry you apply a water bath with very diluted pinacyanol, and let it dry again. As panchro bath sensitizes to red light it has to be performed in darkness, you have to close safe light just before the bath...

pinacyanol is not as cheap, at ebay you can find 1gr some for $100 , but 1gr ca last for ever, it is used in extremly low quantities, the same bath can be used a lot of times until gelatin in a lot of plates has absorbed all liquid.

pinacyanol safety hazards, irritative if 100% concetration: https://pubchem.ncbi.nlm.nih.gov/compound/Pinacyanol_chloride#section=Substances-by-Category

Great fun !

Robert Brazile

19-Jan-2018, 11:11

Thanks, Pere. I'm not being held up by difficulty, just my own stubbornness at performing the previous stages to my satisfaction before moving on. Glad to hear it's as simple as it seemed.

Robert

Nodda Duma

19-Jan-2018, 12:14

Pere Casals

19-Jan-2018, 12:39

Pere,

Water with diluted Pinacyanol can be added to a spare development tank that is already loaded with plates, and then drained out. That way you don't have to fumble with tray-sensitizing and wet plates in the dark.

good idea..

as I see now... a yankee tank can be modified to add an additional hole with a fan on and hepa filter, so drying could be made in the tank itself... with bi-distilled water no drying mark should remain, or perhaps drying marks will disapear in development, without much effect in the image...

anyway sadly I won't get rid of trays, as I'm thinking in 14x17 :)

a mate has an old camera looking firewood... it would be a sin not making plates for it

Nodda Duma

19-Jan-2018, 13:48

Drying marks seem to disappear in development without affecting image, but they are annoying when you see them on the unexposed plate.

Pere Casals

19-Jan-2018, 14:01

Drying marks seem to disappear in development without affecting image

Nice to know it...

andrewch59

21-May-2018, 15:47

Pere Casals

21-May-2018, 17:09

Pere,and Robert seeing your images inspires me to keep trying.
178497
I am prone to waste a lot of emulsion trying to pour plates under red light, a towel draped across my knees collects 75 per cent of the emulsion. I am going to try a coating rod made of wound coated electrical wire, so as not to scratch the glass.

Hello Andrew,

I use the coating table I described in this post: http://www.largeformatphotography.info/forum/showthread.php?140603-Convenient-Dry-Plate-coating-table&p=1401868&viewfull=1#post1401868

It is a way to make perfect coatings, it was inspired in The Light Farm info by Denise Ross.

If you see the drawing the lateral side is a bit higher (0.5mm) than the plates to ensure a consistent coating thickness.

A trick that works nice it's wetting a lot the (glass) table before placing the pates on it, in this way emulsion does not go under the plate (capilarity), resulting a clean back side.

I've also have to say that I had been in Queensland, the city was Emerald, for 2 weeks, it was 10 years ago. This is true Queensland :) impressive !

I got adicted to Vegemite !

Cheers,
Pere

andrewch59

21-May-2018, 19:43

Pere, your table looks ideal! I will still try with the coating rod, I have already bought the bits. The only worry, is at the end of the glass where I will have to put a gutter to catch the excess.

Emerald, yes a great town, I live on the border in the highlands, got down to an impressive -3 last night, that's cold for us.

Nodda Duma

22-May-2018, 06:31

Andrew, you could try my method:

lay glass on leveling table,

use a syringe to put a fixed amount of emulsion on the plate ... 0.25 ml / square inch or 5ml for a 4x5 is ideal in my experience (and, I discovered after determining this, as reported in sources from the dry plate era).

Spread around with a glass rod or similar spreader held ever-so-slightly above surface (spreading by capillary action). Surface tension of the liquid emulsion helps keep it from overspilling easily.

When the entire surface is wet, set your coating rod in a cup of water (avoids buildup). You’ll wipe it off with a lint-free cloth before coating the next.

Slide the plate to the edge of the leveling table and slightly tilt up as needed to let the emulsion better distribute. Slide the plate out of your way to let the coating self-level and set up.

I found you can pretty quickly get good enough to avoid spilling emulsion over the edge. If you do overspill, slide the plate away from the spillage until the spilled emulsion no longer smears. If your emulsion sets up quickly because of higher gelatin %, use less gelatin in the recipe... maybe 6-7% total. I run 5-6%.

I’ve coated thousands of plates this way. Seems to work well.

andrewch59

22-May-2018, 17:31

Thanks Nodda, will give it a try, its got to be better than trying to pour a puddle as in wet pate, the emulsion does not have the same properties as collodion and I seem to end up with most of it on myself

Robert Brazile

25-May-2018, 04:22

Hi Andrew,

Sorry, was away for a couple days. Pere and Jason's suggestions are good, and you should try whatever makes sense to you. Just don't let it stop you, you'll figure it out.

Should you wish to continue trying what I call "waiter-style" (holding the plate with the fingertips of one hand while pouring with the other), I found two things to help considerably with my coating:

1) get one of your larger developing trays (or equivalent, anything that will hold water) and cover the bottom with water, pour over that. It helps you (well, me, anyway) to relax about spillage because it's so easy to clean up, and as a result, I find that spill much less! Still lose a few drops every now and again, but generally I can pour a series of plates without losing much of anything.

2) as you pour into the center of the plate, really concentrate on adjusting the plate in such a way as to keep a round spot in the middle of the plate, and keep pouring until you've covered most of the plate. This will result in needing much less tipping to get to the edges of the plate, which means far less likelihood of overcorrection, which is what leads to the stuff spilling off the opposite edge. It's the overcorrection what does it, you might say.

Regardless, you'll master it, just keep plugging away. I poured plenty of emulsion on hand and arm in the early going, but it didn't take too many sessions before I got there.

Oh, a bonus point: when I first learned to do this, I was taught to warm the plates somewhat before pouring, which I believe sometimes contributed to spillage because the glop ran so much more freely. Since then, the good folks at Eastman have switched to recommending pouring on "cold", i.e., room temperature plates. I found this to be very helpful, because the emulsion spreads a bit more slowly and sets up more quickly. So it's a good thing...provided the room isn't too cold!

I tried it once that way during the winter, and the room was a bit too cold (probably 60F/16C or thereabouts) and the glop more or less started setting up as soon as it hit the plate, resulting in a horrible mess, especially as I tried to recover by spreading it out with my fingers. So the next evening, I got out the food warming tray again to warm the plates, which solved the problem. As soon as the seasons allowed the room to warm up a bit, I was back to pouring without needing the warming tray.

Good luck!

Robert

andrewch59

25-May-2018, 16:15

Thanks for the advice Robert, will take note next session. After looking at the images on the new dry plate thread I am revived to try again. I only have 8x10 glass and find it tricky under red light. The cold plate idea may be a solution.

Robert Brazile

26-May-2018, 03:14

Good luck, Andrew.

I will make one other suggestion, though: could you perhaps start with 4x5? It's pretty easy to cut an 8x10 sheet of glass into 4 4x5s, and they might be a bit easier to learn on. The largest I've poured is 11x14, but not until after I'd done a bunch of 4x5s. These days I pour and shoot mostly 5x7s.

For what it's worth, I copied a glass-cutting jig that Mark Osterman uses that makes the 8x10 -> 4x5 cutting simple, easy, and fast. Just involves a piece of plywood for a base, another piece for a fence, and four brads, placed by careful measurement with a steel rule, which is then used to make the actual cuts. Here is a photo, which I hope is self-explanatory:

https://farm4.staticflickr.com/3950/15323367618_b6ac6fb5d6_c.jpg (https://flic.kr/p/pm5gkq)
D71_6849, 8x10 glass cutting jig (https://flic.kr/p/pm5gkq) by Robert Brazile (https://www.flickr.com/photos/rbrazile/), on Flickr

I made one of my own in about 20 minutes and it's sped up that process considerably. Feel free to ask if you have questions.

Keep us posted as to your progress!

Robert

andrewch59

26-May-2018, 07:49

Robert that looks very effective! I have done a few dozen 8x10 and its where I like to be, use the same format for wet plate, luckily I am 6'6" and have the large hands to ,match so holding the sheet is not such a big deal. The lack of vision is the problem, I poured a wet plate tonight to check the state of my collodion, and it poured fine. I will let you know how it goes with coating, a lot of good advice and I thank you all for your input.

Pere Casals

26-May-2018, 08:46

The lack of vision is the problem,

You can use an IR night vision toy: search amazon.com Spy Gear Ult Ninja Night Vision , $24 https://www.amazon.com/Spy-Gear-Ninja-Night-Vision/dp/B01MSMQHWR/ref=sr_1_1?ie=UTF8&qid=1527349130&sr=8-1&keywords=night+vision+ninja

178617

It´s only a toy but it allows to test night vision in the darkroom, If that way works for you then later you can acquire a more serious model.

andrewch59

28-May-2018, 23:37

178739
A question for the more knowledgeable, does the emulsion go off? I had two black bottles in the fridge. I melted the emulsion down and even put a magnetic mixer in the bottles to smoothen the elixir out. When I tried to use it, it had some lumps in it which were hard to smooth down. Ended up as another big mess, as I then tried to pour the puddle and spread the old way, emulsion everwhere, more over the bench than on the glass.
Losing faith rapidly, when trying to pour, the flow would halt and was very hard to get started again, perhaps the glass was too hot??

Nodda Duma

29-May-2018, 03:03

Can’t say without knowing what your temperatures are or what you are using for emulsion. Not all emulsions are the same.

I melt and hold mine at 40C, apply with syringe onto plates at room temp, and spread with a glass rod. They then have several minutes to flow and self-level. But then, I am sure I’m using a different emulsion recipe than you.

It sounds like you are using pre-made emulsion. Their gelatin content is almost unworkably high for hand-coating dry plates, in my opinion. Mine is 6% and coats just fine. My guess is theirs is more like 10-12% and is a messy pain in the butt.

You can help yourself a little by adding everclear (surfactant) at 40ml / L, but you are better off mixing your own from a lower gelatin content recipe. 5-8% is best for hand-coating dry plates, IMO, giving enough working time to do a good job with less mess.

seezee

29-May-2018, 10:26

Hello Andrew,

I use the coating table I described in this post: http://www.largeformatphotography.info/forum/showthread.php?140603-Convenient-Dry-Plate-coating-table&p=1401868&viewfull=1#post1401868

Pere, what materials did you use? Did you glue it together?

Pere Casals

29-May-2018, 15:06

Pere, what materials did you use? Did you glue it together?

I use a bit of 3M Re Mount spray glue, because I use the same table to coat different plate sizes, if you only want to coat a single size you can use any kind of adhesive, silicone for example.

My base glass is 8mm thick. You can also use a mirror as a base glass. Mirrors have a better flatness than common glass.

andrewch59

29-May-2018, 16:05

Nodda, I have made my own using Mark Ostermans recipe. Once I make the puddle it will pour, then suddenly stop all motion and it take a lot of tilt to get movement again. Of course once you get the flow happening again, it takes off across the plate, and on to every flat surface in the darkroom. Will have to re-check temperatures, perhaps I have everything too hot. I see now there are several new recipes on The Light Farm website. Which one do you use??

Nodda Duma

29-May-2018, 16:51

Osterman’s recipe on The Light Farm?

In step 2, when you add the gelatin to water, you can inadvertently make it too runny if you don’t use the right ratio of water.

To bloom gelatin properly, add the gelatin to 8x the amount of water in ml.

So in step 2 add the 18g gelatin to exactly 144ml of water which will let it bloom properly. This will result in about a 6.6% gelatin solution when all is said and done, and which you may find is easier to coat.

Make sure your emulsion is at 104. Also, add the alcohol and make sure you scrubbed the glass well.

The other thing to try that works: Keep the plate level when you pour the emulsion. Smear the emulsion around with your gloved finger to wet the whole surface, then roll the emulsion around.

Don’t do it the hard way just because someone else does. :)