There are a number of companies out there which do platinum prints and they seem to vary a lot in price. Unfortunately, price isn't necessarily an indicator of quality, and it's hard to know who does the best platinum prints possible..
Gosh you just have to go by reputation. Something like the Irving Penn exhibitions would cost a fortune to replicate, but I guess doing multiple registered exposures to increase dmax could be possible as long as you aren't going 20x24 like Penn did. If you did that I hope you have substantial budget. I could outfit a studio with what that would cost.
I thought the Baryta-based silver gelatin papers were brightener-free and not subject to burnout. I'm not concerned about the silver tarnishing or migrating, since I'd be replacing the silver with gold and/or silver sulfide via the toning process, but the durability of the gelatin layer is obviously of concern.
Some of them are for inkjet like the Hahnemuhle Photorag Pearl and Canson Platine are free of oba content. Many are not. That's right your using gold which wouldn't tarnish even if the gelatin thins out. It will warm your results substantially though. It is hard to know how MUCH toning is needed to "replace" the silver emulstion with gold, probably a lot, meaning pretty significant color change. I know Ansel Adams though his weak dilution of selenium would "replace" the silver but turns out it didn't come close. RIT did a big study of that situation. It's worth looking into how MUCH gold toning is needed to make a "gold metal" print.
Have you seen the positive image which forms on a sheet of paper which has been in contact with a platinum print for a long period of time, e.g. in an album? http://t2.gstatic.com/images?q=tbn:ANd9GcRKnD3x7ZAhti7NnFMOrvk4WzH--r_9cX9ctsa1MQ3_C02fKcvQ
This is caused by the action of sulfuric acid, the formation of which from atmospheric sulfur dioxide is catalysed by platinum. Palladium and gold do not have the same catalyitic effect. Buffering the paper can also prevent this, but, as mentioned before, the platinum (or palladium) printing process requires an acidic environment.
Yes I have, especially in the Steiglitz produced Camera Work original publications, it is all over the place, your right, but it never occurred to me why that ghosting happened.
Platinum printing uses ferric oxalate, which is soluble at an acidic pH, which is reduced to ferrous oxalate by UV light. This then reduces sodium or potassium chloroplatinate, or sodium chloropalladite, to metallic platinum or palladium. Once the print is made, you can deacidify the print and restore an alkaline buffer using magnesium or calcium bicarbonate (conservationists often deacidify prints and documents in this manner), but I'd have to find out if the printmaker can also do this.
That's really interesting. I've never head of anyone "deacidifying a platinum print....
The longevity of carbon pigments is well-known - after all, prehistoric charcoal rubbings on the walls of caves are still visible today, and carbon gelatin printing has been used to produce durable photos since the late 1800s. What concerns me is the longevity of the inkjet receptor layer in the face of UV and chemical attack.
Well, there is Carbon and then there is Carbon. There is a lot of talk about carbon this and carbon that but very few inksets are all carbon. The K7 Carbon Sepia appears to be, or damn close to it. From everything I've read, when you grind pure carbon to the tiny particles needed to fit through an inkjet printer head, and at 2880 dpi at that, you end up with warm. All of the manufactures of premium inks, HP, Epson, Canon use "carbon based" black and grey inks. That is why all of their test results look so good. But with all of them you are blending color hues to neutralize the inks if you don't desire a warm print. In the case of HP their gray inks and designed to match the fade characteristics of their extremely stable color pigments. The hue of the K7 carbon sepia inks are quite warm and this warmth varies with different papers, such as less reddish with the Crane Portfolio Rag, etc, but I personally think having some "hue" to the k7 set makes it even more substantial and dimensional. That's just my taste. I like more warm than say warm-neutral. With a cooling of magenta from the oem inks the magenta layer is going to be the first to go, ( pushing the print toward green ) so the less you "cool" the print generally the better off you are for the long term.
Also, the K7 Sepia seems to have a lot more longevity than the other K7 inks tested - why do you think this is? According to the tests, it essentially doesn't fade, which is what I would expect from a carbon pigment. Are the others not carbon pigments?
None of the others are pure carbon pigments in MY option. I've head people say the neutal set is carbon but if that is so then why is it shifting toward green at a fairly quick rate. I've never gotten to the bottom of that. The K7 "warm neutral" set is also testing really well, but not as well as the carbon sepia, you can already see some little change going on. I wish someone had coated them with one of the UV coatings before submitting, same with the neutrals. I submitted neutral samples in the very beginning but I didn't have the sense to spay one of the samples first with the uv coat. We'll probably never know. The coating didn't help the selenium that much.... I do know that.
Also, what is the colour tone of the Sepia pigment? With platinotypes/palladiotypes, you can achieve anything from a slightly cool tone (pure platinum) to a subtle, warm sepia tone (pure palladium). Also, split toning should be possible by using the related argyrotype method, to deposit silver particles in the paper (instead of platinum as with platinotypes, or instead of silver particles in a gelatin layer) then toning it firstly with sepia (to form silver sulfide in the highlights) then gold toning to completion (to replace the rest of the silver with gold).
Depending on the paper used, the K7 carbon is like a 50-50 mix of platinum with palladium. Somewhere in that zone. I'm not aware of any fade tests of this kind of mix between gold and "sulfide sepa" toners.
What sort of DMax are you achieving with the K7 inks on matte paper? You can re-coat and re-expose a platinum print multiple times ('multilayer' platinum prints) to increase the DMax - Irving Penn did this, and the people at DC Editions also seem to do this: http://www8.clikpic.com/platinumprinting/section444277.html
. Waxing or varnishing the paper would also increase DMax, but I would have concerns about the longevity of such treatment.
My dmax with the K7 carbon on the 9890 on Canson Rag Photographique is 1.66 to 1.67, less on the Crane paper,but beautiful none the less. About the same as my Canon 8300 but less than my HpZ that comes in at 1.8 something.
Storage is a major concern here! The prints won't be stored in a climate-controlled vault - they will be on the walls of a temple which is used daily, in an environment which can vary from very dry (during the dry season) to very humid (during the monsoon) and which cannot ever be called cold or cool!
A pity, because mounting is so good for a print's physical (as opposed to chemical or light) durability, as well as keeping it flat... Perhaps it would be possible to form a platinum print on a sheet of anodised aluminium or titanium, using the oxide layer as a substrate instead of paper?
This is my big issue now. I want to mount my large 40x60 K7 prints to dibond also because when framed they look spectacular and 3 dimensional, but I no idea what adhesives to use and believe me I've looked and asked around for awhile... I call and ask Laumount in NY what they use and they won't return my calls.