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goamules
5-Jun-2020, 07:12
One of the common concerns that wetplate collodion photographers have is how long will their plates last, with various varnishes. Most prefer a varnish that is very long lasting, or archival quality. In 2009 I started an experiment as to the archival quality of Sandarac varnish, that is still ongoing, as of 2020.

Many modern, synthetic materials have been tried, that seem to work well in the short term. Acrylic Polymers such as made by Liquitex are often used. What we know is that in the past, when ambrotypes and tintypes were a new process, photographers used natural varnishes. These are made from materials such as Sandarac, Shellac, or other hard lacquers dissolved in a solvent. These original plates often have survived 150 years and are in excellent condition. Most are stored in Union Cases, or framed though.

My question was how long will Sandarac varnish last in a moderately harsh outdoor environment? I did not compare it to another plate with Liquitex, unfortunately.

The formula was out of Coffer's Doer's Guide, and consists of Sandarac crystals, Everclear ethanol alcohol, and Lavender Oil.

I shot this plate and varnished it in 2009. Somewhere on this forum I think I have it posted. Also here (https://www.flickr.com/photos/garrettsphotos/4012366235/in/album-72157604666036011/). This is how the plate looked in 2009, freshly varnished:

https://live.staticflickr.com/3601/4012366235_bb8ae7a529_z.jpg

I affixed the plate to my front door. There is an overhang, and little direct sun hits the plate, except in the morning, at an acute oblique angle. It hasn't been touched other than moved slightly a few times, in 11 years. The temperature fluctuates between the high 20s in the winter to 107 degrees in the summer. There are frequent rain and dust storms that blast the area. For all intents and purposes, there is no damage or fading of the plate or varnish.

https://live.staticflickr.com/65535/49973155123_c452872afb_c.jpg

Ari
5-Jun-2020, 08:52
Great to know, Garrett.
Mark Sawyer posted somewhere else here recently where he described Sandarac varnish as being "harsh".
I wanted to follow up and ask what makes it a harsh varnish, and what are the alternatives.
Sandarac has been in use for a long time, and seems to be the go-to varnish. The B&S kit includes it as well.

Two23
5-Jun-2020, 09:03
The original formulas used a lot of shellac.


Kent in SD

paulbarden
5-Jun-2020, 09:15
Great to know, Garrett.
Mark Sawyer posted somewhere else here recently where he described Sandarac varnish as being "harsh".
I wanted to follow up and ask what makes it a harsh varnish, and what are the alternatives.
Sandarac has been in use for a long time, and seems to be the go-to varnish. The B&S kit includes it as well.

"Harsh"?? I wonder what he meant by that.
Sandarac is a bit more difficult to use than Shellac, but once you get the technique down, its a fantastic finish. I highly recommend getting a dedicated toaster oven and do the baking of the varnish for about 3 minutes at 200F - you will get a clean mirror finish unlike anything you can achieve with an alcohol lamp. Small plates (5x7 and smaller) can be done easily with a lamp, but 8x10s benefit immensely from baking in a toaster.

goamules
5-Jun-2020, 09:27
One risk of Sandarac is that it uses a lot of alcohol. If your base collodion was "old" it is weaker than fresh stuff. Also, mixed collodion get's weaker as it ages too, probably because of the same problem of it's component collodion aging. You will know it's weak if you try to rub the developed image with your finger or a cotton ball and it tears. When fresh, you can rub pretty hard to get the oysters off.

What happens in these worse case scenarios is the varnish will "melt" the image. You pour the varnish over a plate as always, pool it around for a few seconds, and as you tilt the plate to drain it off, the image gets ruined as it all melts together. Usually only with collodion that is over 6 months old, if not stored in a cold place, or even 1 year if it is. For that reason, I use Liquitex for older chemistry.

Tin Can
5-Jun-2020, 09:45
Noted, good advice

Ari
5-Jun-2020, 10:01
"Harsh"?? I wonder what he meant by that.
Sandarac is a bit more difficult to use than Shellac, but once you get the technique down, its a fantastic finish.


I scan with the lid open, largely because I prefer a black background around the edge. It's also customary to scan before varnishing to avoid dust/flaws in the varnish, a soft varnish sticking to the glass,(dry unvarnished plates won't), and, if you're using Sandarac or other harsh varnish, potential partial or total loss of the image.

I can only think he meant it in relation to scanning a plate, which is where his comment appeared.

paulbarden
5-Jun-2020, 10:21
I can only think he meant it in relation to scanning a plate, which is where his comment appeared.

Ahh, now I understand. He's talking about the possibility of ruining a plate with varnish if the collodion is old. As Garrett states above, if the collodion has aged to a certain point, it becomes much more fragile and is liable to dissolve when varnish is applied to its surface. I've seen it happen a couple of times when testing VERY old collodion: you pour the Sandarac on and within a few seconds, the image starts to blur and slide around the plate. Its an alarming thing to witness. But in this case, I made the plate specifically to test the state of the collodion before making plates that mattered. Since it failed the varnish test, it was discarded as too decomposed.

bob carnie
5-Jun-2020, 10:57
One of the common concerns that wetplate collodion photographers have is how long will their plates last, with various varnishes. Most prefer a varnish that is very long lasting, or archival quality. In 2009 I started an experiment as to the archival quality of Sandarac varnish, that is still ongoing, as of 2020.

Many modern, synthetic materials have been tried, that seem to work well in the short term. Acrylic Polymers such as made by Liquitex are often used. What we know is that in the past, when ambrotypes and tintypes were a new process, photographers used natural varnishes. These are made from materials such as Sandarac, Shellac, or other hard lacquers dissolved in a solvent. These original plates often have survived 150 years and are in excellent condition. Most are stored in Union Cases, or framed though.

My question was how long will Sandarac varnish last in a moderately harsh outdoor environment? I did not compare it to another plate with Liquitex, unfortunately.

The formula was out of Coffer's Doer's Guide, and consists of Sandarac crystals, Everclear ethanol alcohol, and Lavender Oil.

I shot this plate and varnished it in 2009. Somewhere on this forum I think I have it posted. Also here (https://www.flickr.com/photos/garrettsphotos/4012366235/in/album-72157604666036011/). This is how the plate looked in 2009, freshly varnished:

https://live.staticflickr.com/3601/4012366235_bb8ae7a529_z.jpg

I affixed the plate to my front door. There is an overhang, and little direct sun hits the plate, except in the morning, at an acute oblique angle. It hasn't been touched other than moved slightly a few times, in 11 years. The temperature fluctuates between the high 20s in the winter to 107 degrees in the summer. There are frequent rain and dust storms that blast the area. For all intents and purposes, there is no damage or fading of the plate or varnish.

https://live.staticflickr.com/65535/49973155123_c452872afb_c.jpg

Ok so the first image which is warm and golden and the second image is quite desaturated... I am a bit confused

Vaughn
5-Jun-2020, 11:06
Just photoshop differences, I think -- I see no fading or surface defects.

mdarnton
5-Jun-2020, 11:07
In my field, a "sandarac" varnish would be sandarac only. If that's not the meaning here, I wish a better and more accurate term could be used for this discussion, a recipe, even.

A couple of observations from my own field:

-Modern (often acrylic) varnishes have fared very poorly in the art restoration field, losing clarity due to microfracturess, and their inability to be reversed after their faults were discovered, resulting in a relatively serious art disaster. There are recent varnishes that claim to avoid problems and are regarded as safe. . . . just as acrylics were when they were originally used, before their reputation went bad. I wouldn't touch unproven synthetics with a ten-foot pole for at least 50 years, until the actual long-term results are known. A lot of restorers are jumping on that bandwagon, but I"m not one of them.

-Sandarac may be neutral and it's an important component in reversible varnishes, but used alone it has a strong tendency to abrade in really ugly ways.

-Shellac alone proves to be one of the most durable things out there, but when ozidized over time becomes impossible to remove except by abrasion . . . but it doesn't develop optical defects. It is, however, forever.

--Shellac and sandarac together, about 50:50, has been one of the mainstays of violin restoration for almost a century because of it's durability and reversibility. Since it's reversed with alcohol, carefully, that might be a problem in photo applications from what I'm reading here.

I don't pretend to know how any of this applies to picture varnish, but it's worth knowing, and so I thought I'd insert it.

Mark Sawyer
5-Jun-2020, 14:24
For what it's worth, the University of Buffalo did a Pyrolysis gas chromatography-mass spectrometry
(py-GC-MS) analysis of the varnishes used on 2211 historic tintypes, and found the photographers were using all sorts of different formulae.

"Each detected resin appears in historical recipes, but just 24% of the samples have varnish layer constituents consistent with published tintype varnish recipes. Forty-four percent of the tintypes have varnish constituents consistent with formulations recommended for other collodion images, but the varnishes of the remaining samples have no direct literature equivalents. The preponderance of shellac- and Pinaceae-based varnishes suggests that these correspond to inexpensive commercial varnishes, but tintypists may have developed their own preferred mixtures or simply used what was at hand"

"Conclusions

This study represents the first large-scale analysis on the manufacture of tintypes and provides a unique glimpse into the working habits of photographers of the nineteenth and early twentieth centuries. The poor correlation between recommended tintype varnishes and the materials detected on the historical samples serves as a warning to art historians, conservators, and conservation scientists that practices and processes described in the contemporary literature were not necessarily followed by the artists of the day."

http://static1.1.sqspcdn.com/static/f/695156/24768559/1398170991670/VarnishedTruth.pdf?token=ij1wgiDTAhOKWEViGqxyU20FvfI%3D

bob carnie
6-Jun-2020, 04:39
Just photoshop differences, I think -- I see no fading or surface defects.

goamules
6-Jun-2020, 05:44
Correct, I used two different cameras, even different formats, between the 2009 and 2020 shots. Differences in white balance and all, and not very scientific, I should have scanned the image. But in hand, with reflections and all, seems to be a good way to demonstrate my hypothesis. It's a black and white process, don't worry about the color cast, the plate hasn't changed one bit in 11 years.

paulbarden
6-Jun-2020, 06:55
"Each detected resin appears in historical recipes, but just 24% of the samples have varnish layer constituents consistent with published tintype varnish recipes. Forty-four percent of the tintypes have varnish constituents consistent with formulations recommended for other collodion images, but the varnishes of the remaining samples have no direct literature equivalents. The preponderance of shellac- and Pinaceae-based varnishes suggests that these correspond to inexpensive commercial varnishes, but tintypists may have developed their own preferred mixtures or simply used what was at hand"

Fascinating! Thank you for that information. I'm not at all surprised.