Need advice for engaging dry plate.

[Pere Casals]

Drying marks seem to disappear in development without affecting image

Nice to know it...

[andrewch59]

Pere,and Robert seeing your images inspires me to keep trying.

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.

[Pere Casals]

Pere,and Robert seeing your images inspires me to keep trying.

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.in...=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]

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]

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]

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]

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]

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]

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:


D71_6849, 8x10 glass cutting jig by Robert Brazile, 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]

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.