Woodworking(Framing)/Silver Gelatin/Conservation

Hello all,
Not sure where this goes, though technically it is related to B&W Chemistry/paper.

So I've been doing my own framing: cutting, gluing, etc. Now I'm on to experimenting with wood finishes. However, I have discovered that most likely the VOCs in one or more of my wood finishes has turned part of the silver gelatin print yellow, mainly in the mid-tones, from what I'm assuming is a reaction to the small amounts of residual fixer.

So I ask:

What is the 'Conservation' treatment for Silver gelatin prints in regard to the actual frame? I have cotton mat, etc. But none of that matters if the wood will continue to off-gas for months. The biggest culprit seems to be the latex paint, of which I made a swatch that I mistakenly let dry in my darkroom, turning most of my mis-prints floating around bright yellow. But what about 'boiled' Linseed oil? How long will that take for the chemical driers to be completely gone? BriWax with what I'm assuming is mineral spirits? Should I wait a week or longer? Even after wiping wood down with mineral spirits to get rid of sawdust? Another unpainted frame turned a photo yellow as well--from the latter, I'm assuming. Nearly all wood finishes have VOCs so I am somewhat at a loss.

I know a lot (all) contemporary artists use painted white frames. Are they using a special non-VOC paint? Are they letting it dry for a specified amount of time?

Thanks for any input.

Here are some examples. Selenium toned.

Seal the wood with "extra blond" shellac first, don't do any woodworking or finishing work in or near the darkroom. Allow your frames to cure for at least 30 days before using.

Ideally you also want to seal the inside of the frame too - see here (6:30 onwards) for one method of doing so - I'd suggest watching the full set of videos as they are a pretty good introduction to current practices for optimal quality archival framing.

It's a problem which has to be understood in stages. First, how your prints are processed and then mounted needs an appropriate archival protocol. I won't discuss that at the moment. And yes, fresh wall paint can be real bad for numerous kinds of art work. I am expert at framing and wood finishing. I've sold many millions of dollars of specialized wood finishes and have consulted on some of the most expensive restorations and new wood projects in the world, and set up one of the biggest Festool dealerships in the country. Retired from that all now, but still make my own frames. Wood products can transfer acidity or tannins into the edge of mats and mounts as well as outgas natural turpenes, also formaldehyde fumes if the frame moulding is a manufactured composite. Rick has already mentioned coating the inward frame rabbets with shellac (termed rebates in the UK, even though you don't get any money back). It's important to distinguish real shellac from varnish or poly finishes; and you need a couple of coats. It will be alcohol-based and dry quickly for recoating. Never use just any wiping oil. Linseed based ones easily take up to six months to truly outgas, and can impose a VERY serious fire hazard if wiping cloths or brushes are left around even briefly. But even a premium tung-phenolic blend will take a minimum of couple weeks to outgas in ideal weather. Some of the new hybrid water-cleanup finishes will outgas in just a few days, but might have trouble sticking to oily tropical woods. And if the weather is cold, damp, or humid, you have to allow substantially more time than on the product label not only for dry time before recoating, but for cumulative outgassing too. Mineral spirits slows down drying if it soaks into the wood first. You haven't told us any specifics about your frame material itself, which would help, or where you shop for such things.

DREW WILEY said:

Linseed based ones easily take up to six months to truly outgas

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Even the boiled Linseed oil with chemical driers?

DREW WILEY said:

You haven't told us any specifics about your frame material itself, which would help, or where you shop for such things

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I have been experimenting with different materials. One frame is solid Black Walnut (from American Frame) that I've sanded the original stain/lacquer finish off, then wet-sanded 3 coats of BLO. I just finished it with BriWax (Beeswax/carnauba wax). Another is Hard Maple (one from American Frame, others from MetroFrame), that I've experimented with bleaching with a two part bleach of lye and peroxide. I'm not sure if these are a good idea to use next to images though, as I read peroxide can be very discoloring, and I also need to neutralize with vinegar, so without extreme care the pH will probably not be balanced for archival storage. One of these frames I finished with pre-catalyzed spray lacquer, which I let sit outside for a few days, and then placed the mounted gelatin print inside, and put in a closet, after about 3 weeks I got it out and found the above discoloration.

Do you have any recommendations for the most inert finishes? Should I just use raw wood coated with shellac?[/QUOTE]

The first thing you need to do is pay more attention processing your prints. That yellowing won't happen, even with wood frames and some VOCs if the prints are fixed and washed adequately. Too late for already mounted prints, but from now on...

Conservators like metal frames; they are completely inert.

Sealing your finished wood frames with shellac, as mentioned above is good. I imagine that a period of outgassing/curing time (maybe under some low heat) before actually framing your prints would help as well.

Water-base finishes have low VOCs. Pure oil finishes do as well (I'm a tung oil fan). Maybe you need to research and find more suitable finishing materials. Personally, I'd go for a nice hand-rubbed and six-month cured oil finish.

Best,

Doremus

Linseed oil is an unstable fatty acid chain which basically breaks down as it cures. Driers don't change that fact. When I was young, we'd slowly hand-rub linseed oil on gunstocks hour after hour. Without realizing it, what we were doing is using the heat of friction to actually change the molecular bonding of the oil somewhat. What paint manufacturers once did was to do this in big heat vats to created a new kind of product called an alkyd, which was the primary ingredient in oil-based paints for several decades. But then superior tung or soy oils took over. Some of those products were never intended to fully dry, but remain elastic as long as possible. But lots of wood finishing products have BS labeling and are of inferior quality. High quality tung-phenolic or tung-urethane finishes as well as water-based finishes and stains can be found under Daly's and ZAR labels on the West Coast. I'm less familiar with East Coast brands which sometimes get marketed here too. There is a Zinsser product called Sealcoat which is a modified easy-to-use shellac with longer shelf life than ordinary shellac. The use of linseed oils is the no.1 cause I can think of for cabinets shops and furniture factories burning down. It is what burned down the Wooden Duck furniture warehouse in Berkeley a few years ago, and then another big fire in the vicinity just a year later. Rags and so forth will spontaneously combust; they don't even need an ignition source. The no.2 cause was nitrocellulose lacquers, which are now illegal to use in commercial facilities, but are still ironically available for amateur use. ... And Doremus, "pure tung oil" is a marketing myth. If that were the case, you'd have to pry it out of the bottle. It's all modified in some manner or another before it ever gets into a bottle or can, or is even capable of being easily poured. There are all kinds of marketing tricks. My favorite was an oil a local blender claiming his product came from deciphering an ancient formula in an Egyptian tomb, and would hold up on outdoor wood for twenty years on the Hawaiian coast. His market term was "Brazilian Rosewood Oil". It was oiticica nut oil farmed in Brazil, kinda the poor man's tung oil, and lasted about six months at the most. He did get very rich, was a highly colorful old dandy, and recently passed away.

I'm not sure Drew... The product I use is labeled, "100% tung oil." It is produced by pressing, just like other pure oils. Maybe it's thinned with something, but then that should be on the label, right? FWIW, most workers thin pure tung oil 50/50 with spirits for the first coat, since it may penetrate better and dries more quickly. I use it unthinned, but wait weeks for the first coat to dry at times, even in warm weather (I don't even bother working in cold weather).

At any rate, being careful with rags with any finishing oil is really important. I hang mine individually all over the garage to dry before discarding them. Tossing them all into the waste can or a pile before they are dry is tempting fate.

Oils don't really "dry," since there's no water in them to begin with. Rather, they "cure" as they slowly oxidize, which changes the polymer structure of the oil. This takes a long time with many oils, with complete curing not happening for months or even years. Still, after some weeks, the majority of curing is done and the finish is hard enough to be put into use.

Best,

Doremus

I AM sure. Raw tung oil has the consistency of molasses. The first company that propagated the myth was Amazon Tung Oil (no relation to Amazon the distributor). Driers get incorporated into something else added to it, like phenolic resin or urethane. Drying pertains to anything that evaporates, not just water. Curing has a different implication, at least in standard industry jargon. Thinners generally have a different purpose apparent in their name. They don't always help penetration; it depends. The denser the wood is, the shorter the molecular chain of the oil must be. An oil suitable for teak, for example, must be quite different than one meant for a soft porous wood like redwood. Oils are also blended all kinds of ways depending on the application and degree of flexibility desired. Marine finishes require very different formulation than hard finishes. Curing is engineered. Linseed long oils (long polymerized linseed-derived alkyds) were meant to take decades to fully cure, and were one reason why old time oil-based house paints lasted so long. But 90% of retail store products today basically sell junk, especially in the big boxes. Many labels are misleading. Your understanding of these things is basically pre-1930's, or by European standards, pre-1920's, which ain't bad, but what is currently available today is determined by somewhat different factors, including air quality rules. Nowadays chemists experiment with thousands of formulations and keep trade secrets, and then finally just a few of those new things might find a market application. I've seen thousands of little bottles of experimental acrylic resins on shelves behind a bank vault door, each with a number on it. How oils and resins polymerize and eventually cross-link is a complex science. Not all the answers are known. And there are entire categories of wood-finishing technology that most people are entirely unaware of, and that you're not likely to find in any paint or hardware store unless they're quite specialized. Shellac is such a complex substance that it's never been artificially duplicated. Bugs still make it, and you've no doubt eaten more of it, without realizing it, than the amount you've used from a can. The biggest importer of shellac in the world is Sees Candy.

For more than 40 years, I've approached wood frames by leaving the rabbeted glass/mat/print/backer surfaces completely unfinished, then lining them with Tyvek (spun-fiber HDPE) tape:


I cut the tape to a width that, when folded on its long dimension, fits exactly on frames' inner surfaces. The frames range from oak to pine to walnut, with outer (visible) surfaces of the first two stained and polyurethane coated, while the latter are oiled with boiled linseed. In all that time, not a hint of discoloration/deterioration has appeared on any of the mats or fiber-based gelatin silver prints that are dry mounted within.

Wholesale framing suppliers as well as conservation supply houses sell appropriate rabbet liners. BUT any one person's anecdotal experience with this or that product or method is no substitute for the recognition that many factors of display, microclimate, and air pollution potentially come into play overall; so if you are selling framed prints to others, it would be wise to keep the bigger picture in mind. Incidentally, Tyvek is infamous for letting tannins through in the presence of moisture; even building codes stipulate standoff airspacing. It is a droplet barrier, but the presence of condensation (like a poorly insulated frame sandwich using real glass hung on a poorly insulated wall) has a surfactant effect in combination with tannins. In other words, Tyvek is not an acid barrier. Mylar stripping is. It's probably the backing tape itself providing the protection in the case of that Archival Methods product, with the Tyvek serving as more of an inner cushion? If not, supplemental double-faced mylar tape is helpful. But tape adheres better if the rabbet is sanded smooth and sealed with shellac first. Never use masking tape for this. Unsealed pine inners is a very bad idea; it potentially emits a lot of natural turpenes, depending on the species and grade of cut.

DREW WILEY said:

...Tyvek is infamous for letting tannins through in the presence of moisture; even building codes stipulate standoff airspacing. It is a droplet barrier, but the presence of condensation (like a poorly insulated frame sandwich using real glass hung on a poorly insulated wall) has a surfactant effect in combination with tannins. In other words, Tyvek is not an acid barrier. Mylar stripping is. It's probably the backing tape itself providing the protection in the case of that Archival Methods product, with the Tyvek serving as more of an inner cushion?...

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For four plus decades I've had those pictures hanging on reasonably well-insulated walls here in San Clemente some miles from the coast. RH has ranged from the 30s to the 70s most of the time. Condensation has never occurred. All I'm reporting is my experience with those products under those conditions. Others' mileage may vary.

My brother lived on the beach in Santa Barbara and had a terrible time with RH; all his chromes and color prints were ruined except for the ones he sent me to print. Here the foggy conditions present quite a problem with prints hung on perimeter walls of commercial buildings with strong diurnal temp swings. I knew how to hermetically seal prints for a massive upcharge to the framing fee, or else there would be a disclaimer. Things are simply out of one's control once a print is sold. But I did try to research the conditions if significantly different from here. It's fairly easy to add extra fome-core as rear insulation, and acrylic glazing is far better than real glass in that respect.

Unless you want to get deep into the whole world of adequately archival framing, the most painless option I've found are the Halbe frames from Germany - you can have all sorts of environmentally sealed options, coated acrylic glazing, several security options etc - and they are ridiculously straightforward to use. Not cheap, but they are properly designed to pass the relevant photo preservation tests - especially in isolating any wooden parts from the artwork.

I know all about "not cheap". My minimum add-on charge on a hermetically sealed frame was a thousand dollars. It's a lot of work requiring special supplies and equipment. I've known the largest wholesale framer in this town to charge forty thousand for a single large frame. Ironically, they're now way over in the refinery district, not only bad for human health, but really bad for even b&w prints due to sulphur dioxide in the air.

DREW WILEY said:

I know all about "not cheap". My minimum add-on charge on a hermetically sealed frame was a thousand dollars. It's a lot of work requiring special supplies and equipment. I've known the largest wholesale framer in this town to charge forty thousand for a single large frame. Ironically, they're now way over in the refinery district, not only bad for human health, but really bad for even b&w prints due to sulphur dioxide in the air.

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Even with the benefit of relatively heavily cnc aided mass production, Halbe will charge 500-600EUR for a 20x24 'Protect' frame with Optium Acrylic glazing, so your upcharge is not hugely surprising.

The biggest name in UK custom framing (John Jones) shut up shop about a year ago - they were famous for being able to make just about everything and anything frame-wise in-house, though their demise may have had more to do with a bad property investment than the business itself being unsound. Their custom welded metal frames could be quite beautiful & were a whole lot less tacky (and vastly more expensive) than some of the Nielsen profiles. They also contributed quite heavily to innovation in archival framing - paper wrapped fillets (originally wood, then acrylic) were their invention I recall.

I mostly just do routine personal silver print drymounting these days; museum rag board has gotten expensive enough. And I make my own hardwood mouldings, plus still have lengths of Nielsen metal profiles in stock. The big color mounting gear only comes out if there's a special need.

mercurye said:

Hello all,
Not sure where this goes, though technically it is related to B&W Chemistry/paper.

So I've been doing my own framing: cutting, gluing, etc. Now I'm on to experimenting with wood finishes. However, I have discovered that most likely the VOCs in one or more of my wood finishes has turned part of the silver gelatin print yellow, mainly in the mid-tones, from what I'm assuming is a reaction to the small amounts of residual fixer.

So I ask:

What is the 'Conservation' treatment for Silver gelatin prints in regard to the actual frame? I have cotton mat, etc. But none of that matters if the wood will continue to off-gas for months. The biggest culprit seems to be the latex paint, of which I made a swatch that I mistakenly let dry in my darkroom, turning most of my mis-prints floating around bright yellow. But what about 'boiled' Linseed oil? How long will that take for the chemical driers to be completely gone? BriWax with what I'm assuming is mineral spirits? Should I wait a week or longer? Even after wiping wood down with mineral spirits to get rid of sawdust? Another unpainted frame turned a photo yellow as well--from the latter, I'm assuming. Nearly all wood finishes have VOCs so I am somewhat at a loss.

I know a lot (all) contemporary artists use painted white frames. Are they using a special non-VOC paint? Are they letting it dry for a specified amount of time?

Thanks for any input.

Click to expand...

I only use anodized aluminum frames.

mercurye said:

However, I have discovered that most likely the VOCs in one or more of my wood finishes has turned part of the silver gelatin print yellow, mainly in the mid-tones, from what I'm assuming is a reaction to the small amounts of residual fixer.

Click to expand...

-) the term "VOC" is that broad that it is not useful here
-) the discoloration can be inducedd by gases not even originating from the frames. The typical culprit in these cases are Sulfur-containing gases from the generic environment.

VOC's here are primarily regulated in relation to smog formation. But the increasing strictness of these regulations has required the reformulation of most varnishes and paints, and the remaining oil-based, penetrating ones are going to dry a lot slower than they used to, which is an important factor to keep in mind when scheduling picture framing projects. The terrible effects of industrial sulfur dioxide pollution in past times was what once made heavy toning of silver images mandatory. But lots of old images weren't fixed well. Anyone who likes to work with wood frames needs to understand certain basics concerning how wood species and cuts differ, and how modern wood composites routinely contain formaldehyde glues and binder, something very bad indeed outgassing around photographs. But new houses are filled with that too. So timing of displays is important. If you can smell it, or if it gives you a sore throat, it's won't be healthy for your photographs either.
I could recite some extremely expensive horror stories about certain galleries timing such things badly.