How stable is RC substrate?

[sanking]

Putting aside all questions regarding the archival quality of a silver image on RC substrate, how stable is the substrate itself?

I ask this question because a fixed out RC substrate makes a very attractive final support for carbon images.

Perhaps someone would comment, or direct me to relevant studies on the subject?

Sandy King

 

[Photo Engineer]

Putting aside all questions regarding the archival quality of a silver image on RC substrate, how stable is the substrate itself?

I ask this question because a fixed out RC substrate makes a very attractive final support for carbon images.

Perhaps someone would comment, or direct me to relevant studies on the subject?

Sandy King

Sandy;

There are quite a few threads on this here. I have written so much about it I hate to repost it. We can talk about it over dinner (my treat) this June, ok?

But there are patents by W. Venor and others to Kodak on antioxidants in RC and studies by Henry Wilhelm. In conversations with him and with researchers at RIT and GEH, I believe that it is probably nearly as good as FB by now.

Ron

 

[sanking]

Sandy;

There are quite a few threads on this here. I have written so much about it I hate to repost it. We can talk about it over dinner (my treat) this June, ok?

But there are patents by W. Venor and others to Kodak on antioxidants in RC and studies by Henry Wilhelm. In conversations with him and with researchers at RIT and GEH, I believe that it is probably nearly as good as FB by now.

Ron

Ron,

Thanks very much for your reply.

This is really good news to me. For reasons I don't fully understand a carbon image transferred to RD substrate has a lot more dimensional quality than when placed on virtually all other FB surfaces. And, for some reason FB papers sometime cause mottling problems that never happen with RC sustrates.

Sandy

 

[Ryuji]

The right answer is it depends. If you are looking at paper made by major manufacturers, they are pretty stable in normal viewing condition. I've run quite a few tests of RC paper (mostly AGFA, but some Ilford, Oriental and Kodak) under quite severe conditions, but didn't see a single case of deteriorating support, even long after untoned silver image is severely deteriorated.

If you are concerned, limiting the UV in viewing light, as common with color prints, is one thing you can do to ensure good longevity. Dark storage would be no problem.

 

[sanking]

The right answer is it depends. If you are looking at paper made by major manufacturers, they are pretty stable in normal viewing condition. I've run quite a few tests of RC paper (mostly AGFA, but some Ilford, Oriental and Kodak) under quite severe conditions, but didn't see a single case of deteriorating support, even long after untoned silver image is severely deteriorated.

If you are concerned, limiting the UV in viewing light, as common with color prints, is one thing you can do to ensure good longevity. Dark storage would be no problem.

Hi Ryuji,

Thanks for the comment.

I am not in the least interested in the permanence of the silver image on the RC substrate, since I am killing it "a priori" in order to use the substrate itself as a support for carbon transfer pigment prints.

What you and Ron have told me about the stability of the RC substrate itself is very encouraging since it is such a great final support for a carbon transfer image.

Sandy

 

[boyooso]

I was not aware that the silver image was the problem in RC, I had always understood that it was the substrate that was the problem with RC.

Have I misunderstood this all these years?

Corey

 

[Ryuji]

I am not in the least interested in the permanence of the silver image on the RC substrate, since I am killing it "a priori" in order to use the substrate itself as a support for carbon transfer pigment prints.

I know that from your first posting. I just mentioned silver image to tell you that the substrate is always more durable than untreated silver image in my tests. Of course, we all know that it doesn't mean much if you are concerned about long term stability of anything, because untreated silver image is not very durable at all.

The variability across manufacturers I mentioned is also independent of silver image. You should still pay attention to this aspect, since the difference is in the additives to the resin and also the way titanium white pigment is made. In order to make very good RC paper support, the particle size, moisture content, etc. of the pigment must be very tightly controlled. Else the very thin resin layer can deteriorate very easily. Another factor is resin additives. RC paper needs good antioxidants to prevent radical chain reaction that often lead to the cracked resin or other problems when the reaction is not prevented.

What you and Ron have told me about the stability of the RC substrate itself is very encouraging since it is such a great final support for a carbon transfer image.

Well, I have to say the same thing about having skillfully toned silver image on RC substrate. A lot of people use the term RC in derogatory way, and while I agree most RC prints are careless student prints, but there is nothing wrong with the material itself, especially the good ones...

 

[Ryuji]

I was not aware that the silver image was the problem in RC, I had always understood that it was the substrate that was the problem with RC.

There are/were multiple problems with the longevity of RC paper. Cracking resin problem was one of the early problems that were improved relatively early among leading manufacturers from the US, Japan, and the Western Europe. I'm not sure about how other manufacturers caught up.

With current/recent RC papers made by Eastman Kodak, Fujifilm, AGFA, Ilford, the biggest problem is the silver image. Untoned silver image on these paper can deteriorate fairly quickly, depending on the particular storage/display condition, due to environmental pollutants. The same goes to FB prints. All important silver prints should be toned in a sulfiding toner. This is the most well studied and most effective image protection you can give to silver image. Other options include fairly strong selenium toner (KRST 1+9 or 1+4) or gold toners. With the latter the image should be toned fairly deeply. Weak toning is better than nothing but it is not as effective.

Another thing to note is that important films and prints should never be stored in high humidity area. A RH of 30-40% is good but anything above 50% is high risk. Moisture accelerates the oxidative attacks from environmental pollutants.

 

[Michel Hardy-Vallée]

Would Ilfochrome base have even better keeping qualities given that it's a full plastic base? Might be harder to "clean" the paper before, though.

 

[Steve Smith]

Would Ilfochrome base have even better keeping qualities given that it's a full plastic base? Might be harder to "clean" the paper before, though.

This seems an expensive option. The white base material of Cibachrome/Ilfochrome is, I believe, DuPont Melinex which can be obtained quite easily. We have about 7000 large sheets of it here at work!

Steve.

 

[Photo Engineer]

Sandy;

I suspect that we will see a continuing degradation in quality of FB paper, as the market shrinks. I have reports of bad FB and RC from a surface standpoint, but no reports yet on keeping quality.

As for keeping silver or dye images, in the early days of photography, prints were processed 'normally' for the times and many still exist today. I have original family prints about 75 to 90 years old that are still in good condition, but the paper is brittle and you have to be careful with them. The silver image is just fine though. And, I have done nothing special to preserve them nor did the 2 generations of people do anything special when they had the pictures. Many were stored in a hot attic.

I have run tests at room temperature and at up to 140 deg F and 90% RH and with up to 500 FC of illumination. Some of these tests went for years. In the early stages, RC went before the images, but in the later stages of research the image and RC were holding up even at the limits of the test and this worked out to 100+ years of normal keeping.

The plastic support used in Ilfochrome may be stable, IDK having never tested it for stability, but it does last as long as their dyes which are very stable. The use of that support is a requirement due to the strongly acid dye bleach step which would destroy FB and RC papers.

PE

 

[Konical]

Good Morning,

For the last few weeks, I've been in the process of moving. Along the way, I found some of the earliest prints I ever made (mid-1970's). Back then, I was printing only on RC, mostly Kodabrome and Polycontrast. I pretty much just followed basic procedure. I did use two fixer baths, but no HCA or toning. Washing was in a tray with siphon. I know I was a lot less aware then of lots of things photographic, including some of the finer details of processing prints. Nevertheless, all the old prints and contact sheets I reacquainted myself with show no detectable signs of deterioration, either in image or support base. I have no idea about materials kept in continuous light, but the stuff I have seems to be holding up rather well.

Konical

 

[sanking]

This seems an expensive option. The white base material of Cibachrome/Ilfochrome is, I believe, DuPont Melinex which can be obtained quite easily. We have about 7000 large sheets of it here at work!

Steve.

There must be different types of Melinex. I understand that it was used as the final support in the Ultrastable color carbon printing process and it obvioulsy worked very well in that application. However, someone sent me a few packets of Melinex a couple of years back and it did not work well at all in single transfer carbon. The image stuck to the surface very well, but there was some kind of micro-porous structure that prevented some of the soluble pigmented gelatin from washing out. This left a low contrast image with dull highlights.

Sandy King