DIY Dark Slides

[eric black]

I may need to make some dark-slides for some 8x10 holders I bought that arrived damaged. I have searched the forum and online and have found the following as possible materials, both available from McMaster. Material #1 is Deldrin and material #2 is garolite. Garolite comes in two possibilities, one is electrically insulating and the other is electrically conductive (for 3-4x the price of the insulating). Anyone have any experience with any of these as far as ease of cutting and feasibility in use. If Garolite- is the electrically conductive worth 3-4x the price as far as keeping dust issues with the holders to a minimum? Any experience/advice is appreciated-thx

[Eric Woodbury]

If it is a problem, spray them with staticide. I wouldn't spend the extra dough.

[Michael Kadillak]

I may need to make some dark-slides for some 8x10 holders I bought that arrived damaged. I have searched the forum and online and have found the following as possible materials, both available from McMaster. Material #1 is Deldrin and material #2 is garolite. Garolite comes in two possibilities, one is electrically insulating and the other is electrically conductive (for 3-4x the price of the insulating). Anyone have any experience with any of these as far as ease of cutting and feasibility in use. If Garolite- is the electrically conductive worth 3-4x the price as far as keeping dust issues with the holders to a minimum? Any experience/advice is appreciated-thx

A DYI in dark slide material is a slippery slope. I tried two different materials of necessary thickness that looked suitable for dark slide material and they both exhibited light leaks on testing. I am defaulting to Intrepid Camera company in the UK as they have both the correct material as well as the capability of properly cutting it to the correct dimensions. When they get a break in their schedule, I believe they are going to do a run of 8x10 dark slides. Ping them relative to your interest.

[Nodda Duma]

I’ve successfully tested 1mm thick black ABS / styrene

[Drew Bedo]

I have heard of Formica sheets used for a replacement dark slide... . .

[Michael Kadillak]

I’ve successfully tested 1mm thick black ABS / styrene

The material I ordered from National Plastics sounded like a similar ABS/Styrene material. I exposed a test sheet and to the eye it looked at least at first pass as acceptable and I was encouraged to order more material and scale up. Then I had to remind myself that it was really not a scientific test at all. I took a step back and loaded one side of a Fidelity holder with the replacement dark slide and kept the original dark slide on the opposing side. I exposed both sheets to the identical scene and processed then identically and trimmed a corner of the test dark slide so I could distinguish it and initially put the two negatives over a light table and then checked them with a densitometer. I could immediately tell that in certain random areas of the negative a subtle amount of light was in fact making its way through the test dark slide material that was confirmed with the density readings. Glad that I did not scale up on that project. Waiting for Intrepid to fill the billing and then I will load up knowing that all is well. Film costs and a desire to minimize risk at least for me drives this decision.

[eric black]

The material I ordered from National Plastics sounded like a similar ABS/Styrene material. I exposed a test sheet and to the eye it looked at least at first pass as acceptable and I was encouraged to order more material and scale up. Then I had to remind myself that it was really not a scientific test at all. I took a step back and loaded one side of a Fidelity holder with the replacement dark slide and kept the original dark slide on the opposing side. I exposed both sheets to the identical scene and processed then identically and trimmed a corner of the test dark slide so I could distinguish it and initially put the two negatives over a light table and then checked them with a densitometer. I could immediately tell that in certain random areas of the negative a subtle amount of light was in fact making its way through the test dark slide material that was confirmed with the density readings. Glad that I did not scale up on that project. Waiting for Intrepid to fill the billing and then I will load up knowing that all is well. Film costs and a desire to minimize risk at least for me drives this decision.

Great info everyone- Michael- do you have a contact at or reference point for the Intrepid possibility?- I have looked at their facebook page and see only camera related references there- an email address or reference would be great to know

[Michael Kadillak]

182561

[Michael Kadillak]

Attached above is a screenshot correspondence that came to me when I contacted Intrepid Camera Company about producing dark slides for Fidelity / Lisco 8x10 film holders from the material they showed on their website. This was from April of 2018 so my feeling is that if more interest was expressed it would help the cause. They have the CNC machines as well as the ability and desire to acquire the proper dark slide materials in bulk. Plus the camera company is in business solely to support large format photography which one can clearly see from their web presence.

[Marky]

Michael, that's PR talk. Intrepid 8x10 Dark slide is not happening anytime soon, they're refunding all Kickstarter backers who ordered the dark slides. Also they are running another KS for a Graflarger so there probably no resource to do the dark slides, and they also don't have the necessary machinery. Don't get your hope up.

https://www.kickstarter.com/projects/1436129614/intrepid-8x10-camera-an-affordable-large-format-ca/posts/2252812

Eric, just buy another used Fidelity - there's one for $80 on Igor's camera right now.

[rfesk]

A friend once made a dark slide out of a sheet of brass. For a smaller format film holder.

[Nodda Duma]

Michael, you really have to pay attention to how much pigment is used in the material. Normally there may be 1-3%, but you can get 10% pigment ABS which is specifically designed for light-blocking. You can it in colors other than black (white, for instance). RTP is a common source for this type of ABS. Sounds like you might have gotten the wrong type of plastic.


Michael, that's PR talk. Intrepid 8x10 Dark slide is not happening anytime soon, they're refunding all Kickstarter backers who ordered the dark slides. Also they are running another KS for a Graflarger so there probably no resource to do the dark slides, and they also don't have the necessary machinery. Don't get your hope up.

https://www.kickstarter.com/projects/1436129614/intrepid-8x10-camera-an-affordable-large-format-ca/posts/2252812

Eric, just buy another used Fidelity - there's one for $80 on Igor's camera right now.

That's actually good to know, because I was going to reach out to them about making new dry plate holders. Sounds like I don't have to bother. If they can't make dark slides, then they can't make plate holders, either.

-Jason

[Michael Kadillak]

Michael, that's PR talk. Intrepid 8x10 Dark slide is not happening anytime soon, they're refunding all Kickstarter backers who ordered the dark slides. Also they are running another KS for a Graflarger so there probably no resource to do the dark slides, and they also don't have the necessary machinery. Don't get your hope up.

https://www.kickstarter.com/projects/1436129614/intrepid-8x10-camera-an-affordable-large-format-ca/posts/2252812

Eric, just buy another used Fidelity - there's one for $80 on Igor's camera right now.

Thanks for the info. This is why we share pertinent information on the topic of the day. What I learned from my iteration into the world of plastics is that I was completely out of my league floundering with attempts at finding the correct light tight properties at the desired material thickness. Even the quasi experts I engaged in this process let me down.

What we do know is that if we approach this situation as a collective body the solution has a higher degree of favorable resolution. What I gleamed from the Intrepid dialog was that they claimed to have researched and in fact found the correct material from which to make dark slides from and had a pallet of it that they purchased in a video I saw a while back. If they are not doing anything with the material I wonder if they could part with some of it or share with he LF community the specs of it and where they acquired it?
I would also think that the collective body here may know where we could contract a company that could cut a template dark slide for us and what it would cost for these services? I have a dozen brand new Lisco 8x10 holders that I would like to match with a beefier dark slide than what they came with and would easily purchase three dozen replacement dark slides by myself.

[Vaughn]

A friend once made a dark slide out of a sheet of brass. For a smaller format film holder.
And I have 8x10 and 11x14 holders with metal darkslides -- definitely heavier, but no worries of light leaking thru them! Tough sonsofaguns, too.

[eric black]

Yep, this is all good information and I think a solution would be great for our community for the following reasons- 1. plastics age (and not in a good way), and 2. No one is manufacturing the slides which are the part most prone to breakage in film holders anymore. I work in a chemistry lab that deals with polymer and materials-based research (although admittedly I hang on the liquid side of the discipline), so I brought in a piece of broken dark-slide this morning and have the following to contribute based on some instrumental and optical data. Looking at IR spectral results for the material and comparing the results to online libraries, it appears dark slide plastic material is a blend of polyvinyl acetate, polyethylene (about 4:1) and a small amount of polyvinyl chloride. Looking at a fracture surface under a microscope, you can see the material likely has carbon black reinforcement and is a cast (vs extruded) material. The carbon reinforcement, if I am correct will make the material stronger when cast, but likely helps with the light-fastness as well. What this says to me is that dark-slide plastic material was more than likely a custom cast blend of polymers that were likely custom made to supply the film-holder industry and likely if there was another market the material was made for, it might be hard to identify. Odds are that it is no longer manufactured since no one is actively making the plastic type filmholders anymore (am I correct with this statement?). Short of identifying the manufacturer and getting them to make more material, our only option for finding a replacement might be identifying another material that is commercially available that has the properties we need to keep the film protected from light and operate smoothly in the holders we can find used. I guess Ill bite the bullet and get a few things and see what I can find out- in the mean time, I like the idea of the community contributing anything they might know that works or not so we can come up with a decent solution (that ideally isn't expensive).

[Michael Kadillak]

Yep, this is all good information and I think a solution would be great for our community for the following reasons- 1. plastics age (and not in a good way), and 2. No one is manufacturing the slides which are the part most prone to breakage in film holders anymore. I work in a chemistry lab that deals with polymer and materials-based research (although admittedly I hang on the liquid side of the discipline), so I brought in a piece of broken dark-slide this morning and have the following to contribute based on some instrumental and optical data. Looking at IR spectral results for the material and comparing the results to online libraries, it appears dark slide plastic material is a blend of polyvinyl acetate, polyethylene (about 4:1) and a small amount of polyvinyl chloride. Looking at a fracture surface under a microscope, you can see the material likely has carbon black reinforcement and is a cast (vs extruded) material. The carbon reinforcement, if I am correct will make the material stronger when cast, but likely helps with the light-fastness as well. What this says to me is that dark-slide plastic material was more than likely a custom cast blend of polymers that were likely custom made to supply the film-holder industry and likely if there was another market the material was made for, it might be hard to identify. Odds are that it is no longer manufactured since no one is actively making the plastic type filmholders anymore (am I correct with this statement?). Short of identifying the manufacturer and getting them to make more material, our only option for finding a replacement might be identifying another material that is commercially available that has the properties we need to keep the film protected from light and operate smoothly in the holders we can find used. I guess Ill bite the bullet and get a few things and see what I can find out- in the mean time, I like the idea of the community contributing anything they might know that works or not so we can come up with a decent solution (that ideally isn't expensive).

Wow. That is great Eric. Having access to those analytical resources is amazing and a thoughtful way of honing in on the process of scouring the market for an alternative material. I think it is safe to say that the company that produced Fidelity / Lisco holders is long gone and likely any internal technical reference assistance that they could be extracted from them is gone also. Is the same material used for all size holders 4x5, 5x7 and 8x10?

I sent a note to Intrepid Camera Company this morning inquiring about any assistance they could provide since it was pointed out earlier that the film holder segment of their strategic business development plan is being effectively displaced by other projects and/or business plans as the company goes through the arduous process of the allocation of their time and resources.

Earlier online videos and comment documented that Intrepid had researched a suitable dark slide replacement material. I requested some business transparency to the material and vendor from which this material was procured (you just never know until you ask) but even a sample of their material for a test as Eric did with the original dark slide material would be a great confirming analytical data point.

I see the steps in this process as: 1) finding the correct material to make the dark slides from and I realize this could take some time, 2) securing a place to procure the material from as well as the costs, 3) find someone who has the capability to cut these for us (could be a CNC process or someone handy with a template and a proper router bit, 4) coming up with a net sales costs per dark slide and 5) assessing the aggregate demand and packaging this up to get the product cycle completed and to the customers.

Daniel Stone on this forum has a business where he provides products to the LF community online. Since he is already set up for this venue I would toss out his name as a person who may be willing to be the point person having already been set up to do this.

I am just looking for the most efficient way to get this project in the done column so more photographs can be made now and down the road.

[B.S.Kumar]

I am talking to one workshop here. The owner is away on a business trip to Europe and the US now, and I hope to have some information by the middle of October.

Kumar

[Marky]

If they are not doing anything with the material I wonder if they could part with some of it or share with he LF community the specs of it and where they acquired it?

Max Grew (founder of Intrepid) actually shared that info:

http://www.largeformatphotography.info/forum/showthread.php?142915-Replacement-8x10-darkslides&p=1432920#post1432920

[Michael Kadillak]

Max Grew (founder of Intrepid) actually shared that info:

http://www.largeformatphotography.info/forum/showthread.php?142915-Replacement-8x10-darkslides&p=1432920#post1432920

Thanks Marty. I remember the video just could not place it. Does FR4 or High Carbon ABS register with anyone relative to a specific product here in the US that someone could chase price and availability? I would think that acquiring aluminum and anodizing it black would be the most costly alternative but this is just a conjecture on my part with no facts to back it.

[Steve Goldstein]

It looks to me like therr might be some confusion here regarding the term “dark slide”. In some countries this term refers just to the flat black that sheets, often with handles of some type, that are used in film holders. In other countries it appears the term is applied to the entire assembly, hence the term “double dark slide or DDS.

I could be wrong, but I believe what Intrepid have been having trouble with is manufacturing the complete film holder, not the dark slide itself.

[desertrat]

Just out of curiosity, does anyone know what the dark slides from nearly century old wood and metal film holders were made of?

[Michael Kadillak]

It looks to me like therr might be some confusion here regarding the term “dark slide”. In some countries this term refers just to the flat black that sheets, often with handles of some type, that are used in film holders. In other countries it appears the term is applied to the entire assembly, hence the term “double dark slide or DDS.

I could be wrong, but I believe what Intrepid have been having trouble with is manufacturing the complete film holder, not the dark slide itself.

The problem with the entire double sided film holder and not the dark slide itself is the impression I got as well Steve.

I did some digging into FR4 material online last night and it appears to be a circuit board material that has a fiberglass component and it comes in various colors and grades as well as thicknesses including the 0.9mm designated as the correct one for dark slide application. That said, finding which "grade" is the correct one and a vendor where you do not have to acquire an entire pallet at thousands of dollars capital outlay would be great. Given we are in the process of a trade embargo with China and this appears to be here much of what I found online is shipped from I was wondering if anyone has a source for a stateside vendor of this material that we could consider initially for a sample evaluate and test and potentially later on for a supply size that is manageable for the interest expressed. Sometimes these companies have internal facilities for contracting the cutting. I am under the assumption that the majority of the interest in dark slide replacement will be with the standardized 8x10 Fidelity / Lisco holder. Folks with wooden holders or other brands of holders with differing dimensions may want to have their own dark slides cut themselves. Kumar located Toyo replacement 8x10 dark slides for me as well as the 90 degree angle screws for these holders.

[eric black]

182701182702
so here is where I am on this project-
from an intact dark slide, a template was made. From the template I used a templating bit on a router and milled the only material I had on hand that I thought might work. I also have 4 more materials coming from McMaster and will be getting some edging material to finish off the pull tab (not pictured- but planning to do a traditional loop-style pull with the plastic edging I have coming). The pics at this point are the template which gets double sided tape in each corner to hold the material in place during routing, the white strips are shims so the material sits flat during the cutting process. Pic 2 is the first prototype made from CPVC. The pros of this material- cheap ($7.27 for a 12"x12" sheet),machines very nicely, very tough and flexible, the correct 0.030" thickness, slides in and out of a fidelity holder very smoothly, and from what I can tell in a crude test in my darkroom, is completely non-transmittant to light. The cons so far- a bit static-y and the color is gray, not black (not sure if this will affect function at all, but it looks kind of cool). Ill continue to update this post with what I figure out from other materials and I plan to do film tests at some point in the near future- but would like to find some cheaper film than what I have on hand to do that with. More to come...

[Colin Graham]

Cool, thanks for sharing your results.
I've always used 1/32" Garolite XX (https://www.mcmaster.com/85315k415), but have heard that some batches are not quite opaque.

[Michael Kadillak]

Cool, thanks for sharing your results.
I've always used 1/32" Garolite XX (https://www.mcmaster.com/85315k415), but have heard that some batches are not quite opaque.

That is what I found with my iteration. I was lured into the conveniences of being able to acquire inexpensive black materials only to find that the requirements of 100% light blockage was never contemplated by the manufacturer or the seller.

As a result I am convinced that the optimal dark slide material must have a fiberglass layer for strength and a secondary layer for light tightness all in a 0.9mm thickness and black in color. FR4 seems like the ticket. I am going to see if I can get a sample of this material to see if Eric can do a test on it.

[Colin Graham]

Testing is important, yes. There can potentially be variations within a single sheet of material. A 15 minute soak in direct sunlight is the most my filmholders will ever endure, so that's the test I use.

[Andrew O'Neill]

And I have 8x10 and 11x14 holders with metal darkslides -- definitely heavier, but no worries of light leaking thru them! Tough sonsofaguns, too.

I have a few 8x10 holders with metal slides. They are my favourites.

[Michael Kadillak]

After some research on the topic and the advice of a highly skilled machinist friend, I have decided to proceed with anodized aluminum for dark slide Fidelity / Lisco 8x10 holder replacements. Fortunately Kumar was able to get me hooked up with Toyo 8x10 replacement dark slides and holder pins at a reasonable price. Should be good to go after this iteration.

[eric black]

So after receipt of the other material candidates from McMaster I have the following to report. Items received were the black deldrin, two types of nylon (black and black slippery) and garolite sheets. The deldrin and both nylon samples failed the light transmittance test. In this test I go into the dark room with a high intensity LED flashlight with a light tight shroud over the front and hold it to the back of the sheet and see if light gets through to the other side. Only the garolite and the aforementioned CPVC sheets (see earlier posts) passed this test. Both were found to be inexpensive, light tight, easily machinable and the correct 0.030" thickness which allowed them to easily be manipulated in the slot of the film holder. My hope was to make the pull section with a plastic push on trim (item 86875K92) but it seems a bit too flexible and so far I haven't identified an adhesive that can secure it to either material. I may just machine the pull tabs in the final iteration or see if I can find some aluminum edge material that will stiffen the tops and make them easier to pull. I will be taking film this coming weekend and doing the final light test by exposing it, cutting it in two then placing one half of each piece behind the slide candidates in the holder for exposure of the closed assembly to the sun for 10-15 mins. I report results after developing. I don't have a densitometer, but I think I should be able to see fogging if it happens.

[Michael Kadillak]

So after receipt of the other material candidates from McMaster I have the following to report. Items received were the black deldrin, two types of nylon (black and black slippery) and garolite sheets. The deldrin and both nylon samples failed the light transmittance test. In this test I go into the dark room with a high intensity LED flashlight with a light tight shroud over the front and hold it to the back of the sheet and see if light gets through to the other side. Only the garolite and the aforementioned CPVC sheets (see earlier posts) passed this test. Both were found to be inexpensive, light tight, easily machinable and the correct 0.030" thickness which allowed them to easily be manipulated in the slot of the film holder. My hope was to make the pull section with a plastic push on trim (item 86875K92) but it seems a bit too flexible and so far I haven't identified an adhesive that can secure it to either material. I may just machine the pull tabs in the final iteration or see if I can find some aluminum edge material that will stiffen the tops and make them easier to pull. I will be taking film this coming weekend and doing the final light test by exposing it, cutting it in two then placing one half of each piece behind the slide candidates in the holder for exposure of the closed assembly to the sun for 10-15 mins. I report results after developing. I don't have a densitometer, but I think I should be able to see fogging if it happens.

Great!

May I suggest a test I used for being able to ascertain added FB+F for the infrared light source on my infrared monocle.

Put a piece of black electrical tape on the emulsion side of your sheet film in total darkness and insert the film with the tape into the holder. Without making an exposure of the sheet film leave the holder with the test slide material inserted facing the sun for 15-30 minutes. Pull the tape off of the film before you develop the unexposed film and you will have a sharp edge of potential density to evaluate or not. Put this over a light table and if you cannot see any hint of density ascribing the space the electrical tape occupied on the film, you should be good.

I contend that the only acceptable test result is zero added density irrespective of how small it may be. Why? because it its likely a linear relationship with increased time exposure to the light source and that is simply unacceptable. Ran into this issue with the density added by the infrared monocle IR light source which glows a red color when it is on. There was a increase in density that is easily remedied by bounding an LED IR light source off of an adjacent wall so only IR comes into the viewing area allowing one to take out the batteries on the monocle IR light source. Yet many folks on this forum commented that although some density was added using the monocle IR light source, it was not enough to be worried about which begs the question, when it some density too much density?

[Peter De Smidt]

Anyone make any progress with this?

[reddesert]

FR4 and G10 glass reinforced epoxy are pretty common materials due to their use in PCB manufacture (I believe they are the same except that FR4 is fire retardant). It may be a little harder to get 0.9mm = 0.035" specifically, but I'm sure someone makes it. It also should not be super expensive.

Here's a supplier that advertises black FR4/G10 in 0.031" thickness in sheets up to 36x48", which costs $42 (probably make about 15-16 darkslides): http://www.americanepoxy.com/g10fr4sheet_Black.html

Here's a supplier that only advertises thicknesses down to 0.06", but you could always call and ask if they can get thinner sheets: https://www.eplastics.com/sheets/micarta/g10-fr4
I have no experience with these suppliers, I just found them by searching for black FR4.

FR4 is not terribly hard to cut with a fine toothed saw, and clean up with sandpaper, so it would be possible for a hobby builder to order a sheet and try to make some darkslides at home. Some of these suppliers offer cutting/machining services, so if you can make a mechanical drawing, you might be able to get darkslides manufactured (if you can forgo handles).

[tigger_six]

Is metal not a reasonable substitute? I recently replaced a polaroid 405 holder dark-slide with one fashioned out of a steel sheet at it seems to work well.

[Tin Can]

Metal is fine.

If I remember correctly some metal slides from 1/4 plate Pack Film holders fit as replacement for Polaroid 405. But not the question here.

Some want new slides for 8X10.

My cheapest solution is to buy more film holders and use the best parts.


Is metal not a reasonable substitute? I recently replaced a polaroid 405 holder dark-slide with one fashioned out of a steel sheet at it seems to work well.

[Jerry Bodine]

If it is a problem, spray them with staticide. I wouldn't spend the extra dough.

I'd recommend a product called Brillianize to stop static electricity on your finished dark slides. Just spray it on and wipe off with a microfiber cloth. There was not long ago another photographer who was experiencing static when working in cold, dry air in Death Valley. I suggested this product and got a report that it indeed resolved the issue. It's available from several sources:

https://www.framedestination.com/framing-accessories/cleaning-supplies/brillianize-acrylic-cleaner-polish.html
https://www.tapplastics.com/product/plastics/cleaners_polishes/kleenmaster_brillianize/112

[chris_4622]

I was the original poster in another thread who wrote of the problems I had with Garolite xx.

I had some left over aluminum pieces that were the right thickness so I made those up into dark slides. The problem with a material that is that stiff is that it is prone to leaking light between the light trap and dark slide if there is any pressure on the aluminum. It's too stiff. It should be noted size matters, on 4x5 I doubt there would be a problem but as you increase the dimension going across the light trap there is a greater chance of deflection causing a leak.

This was my experience with the holders I made. It's quite probably my method for constructing the light trap that is the weak link. I didn't take the time to do it the way Fidelity constructed the traps in my 5x7 holders. There they used two different types of metal at two different thicknesses to perform two distinct functions. The "fingers" in the brass piece would compensate for deflection in the dark slide material. Since I didn't follow this method I ended up with problems using aluminum.

As a side note, I'm in the process of helping a friend construct two wet-plate cameras that are 24" x 24". We are using Garolite XX for the dark slides. I doubt ISO 2 will be sensitive enough to pick up any radiation for the duration that it will be exposed...

[Jimi]

I have nothing to add, but a question: what darkslide material does the Chamonix holders use? I've seen it described as "carbon", but I don't own such holders, so I can't make any comment on its qualities.

[Peter De Smidt]

Well, one can buy all sorts of carbon fiber sheet. Carbon as a pigment is pretty good at blocking light.