Waxing pt/pd prints

[Doug Howk]

Louis Nadeau, in his "History and Practice of Platinum Printing", does question some of the claims for permanence of platinum prints. And I've seen elsewhere the question of its permanence (something about it being used in catalytic converters ).
But I'm not sure how waxing would improve a pt/pd print for permanence (its not like the platinum was suspended in an emulsion layer). I've tried waxing with COT320 but saw only negligible increase in gloss. I wouldn't try it on papers with more texture for fear of damaging the paper.
As to fumed silica, I don't have a reflective densitometer so can't guarantee that it does increase DMax. And it does create another possible failure point - uneven coating.

[sanking]

Hi Michael, you can get a similar dmax enhancement by over printing with gum. It will give a slight sheen to the print similar to wax. It might be worth experimenting with if you get the itch?

Gum over platinum is a old technique that has many variations. If protection is the issue you simply roll a thin coat of gum on the platinum print, dry, expose and develop. This adds just a bit of sheen. An even more interesting technique would be to put a second gum coat on the platinum to enhance the shadows and use the same negative to print. Or better, you could print a second negative just for the shadows.

Finally, you could also coat the platinum print with a thin layer of clear gelatin solution. I have done this several times and it adds a big boost to Dmax. I do it the same way I coat art papers for carbon printing, i.e. use 4-5% gelatin solution (make sure it is clear, some gelatins have very beige color), and roll the coating on with a threaded rod that leaves a wet coat height of about .4 mm. This dries down to about 1/10 this height, but even this thin the gelatin coating adds considerable Dmax to the platinum print.

Sandy

[ridax]

But I'm not sure how waxing would improve a pt/pd print for permanence (its not like the platinum was suspended in an emulsion layer).

I am not sure either. Any wax would make a kind of barrier between the atmosphere and the Pt (or silver or whatever). But how strong the barrier would be - depends on the kind of wax used and the method of its application. Personally I don't know what is the best way to go, and verifying that would take several lifetimes perhaps ;). But still studies carried out on encaustic painting had shown that a highly purified grade of beeswax is able to protect even the pigments of doubtful stability well enough. Pigment particles finely dispersed in melted wax of the sort and thus thoroughly covered with the wax, became insoluble even when boiled in strong acids for hours.

[Drew Wiley]

Beeswax would be a horrible idea. It yellows and potentially traps contaminants. I don't know how "purified" it can really get. The correct wax would be Renaissance Wax, which is a controlled microcrystalline paraffin made specifically for such applications. But as a mere aesthetic opinion, waxing a platinum print seems like
an abomination. Much of the beauty of these things lie in the character of the paper itself. Since Pt/Pd prints tend to be float mounted (as opposed to permanently
drymounted), you'd have to seal the back too. ... then not even a paper hinge will stick to the wax. Gelatin seems like a safer option. But for some reason, I just
can't quite understand why one would want a platinum print look like a silver one. ... I've certainly seen it done.

[ridax]

Beeswax would be a horrible idea. It yellows and potentially traps contaminants. I don't know how "purified" it can really get. The correct wax would be Renaissance Wax, which is a controlled microcrystalline paraffin made specifically for such applications. But as a mere aesthetic opinion, waxing a platinum print seems like an abomination. <...>

The grade of beeswax they used for encaustic painting was purified to the extent it no longer contained softer components and melted only at 100°C (as opposed to 65°C for raw beeswax). It was also bleached by sunlight and didn't yellow again (as chemically bleached beeswax may). The procedures involved were somewhat complex... Carnauba wax is way harder from the start and perhaps doesn't need that kind of preparation. A hard grade of paraffin is also acceptable; it's only drawback is its microcrystalline structure that sometimes is said to give a grainy look to some surfaces.

Though I certainly agree there are lots of aesthetic as well as practical (mounting, etc.) issues with waxing prints, be they Pt/Pd or any other type.

[jonreid]

Michael,
For what it's worth, I once saw a small reference to Richard Sullivan, of B+S, soaking a dried Pt/Pd print in a weak solution of Liquitex Acrylic gel medium.
"After 25 minutes in an archival washer I dry the prints face up on fiberglass screens and then soak each for one minute in an 6% solution of Liquitex Acrylic Gel Medium which increases the Dmax and tonal separation, cools the print color slightly, and also gives the print a slight amount of glossiness."
An APUG thread here: http://www.apug.org/forums/forum42/8...rylic-gel.html

I've been meaning to try it on a dud print to see the effect. The acrylic medium is cheap and easily available from art supply stores.

Jon

[Ken Lee]

I've tested that gel and it's one of the modern materials whose long-term stability I found more dubious than any increase in dMax it might offer.

We get a similar effect by placing the print behind glass when framing - with no danger of cracking, splitting, reticulation, etc.

[Rick A]

For years, I used Kodak ferrotype solution (gloss finish) on my print dryer with FB prints. This was nothing more than beeswax in a solvent (and smelled horrible). I have used Renaissance wax on my dryer in hopes of achieving the same(or similar) look, with much success. Renaissance Wax is not hazardous, nor does it contain any hazardous materials. It is highly recommended for museum restoration and conservation of antiquities.

[Jim Andrada]

Put another way, I think the posts by Ridax are making the point that Pt/Pd while in and of themselves very stable, are also strong catalysts and hence can be very "bad neighbors" and accelerate the deterioration of things in their vicinity - like, for example, the paper on which they're coated.

[Drew Wiley]

So ya gotta be careful and make sure your paper doesn't have iron impurities etc either from mfg or processing water... etc.