platinum prints

[cliveh]

Please excuse my ignorance, but in the past I have been to exhibitions displaying all platinum prints, such as a Linda McCartney exhibition and I very much admire their quality, particularly the blacks. However, having never produced a platinum print myself, can anyone tell me how these can be readily identified? I ask the question because I recently visited a mixed exhibition of prints, where some were labelled as platinum prints, but from past experience I doubted if this statement was true. Is it sometimes possible for unscrupulous photographers to pass silver prints off as platinum?

[Trevor Crone]

Please excuse my ignorance, but in the past I have been to exhibitions displaying all platinum prints, such as a Linda McCartney exhibition and I very much admire their quality, particularly the blacks. However, having never produced a platinum print myself, can anyone tell me how these can be readily identified? I ask the question because I recently visited a mixed exhibition of prints, where some were labelled as platinum prints, but from past experience I doubted if this statement was true. Is it sometimes possible for unscrupulous photographers to pass silver prints off as platinum?

Clive, platinum/palladium prints should be quite matt with the image appearing to sit just on the surface. Some, depending on the actual technique used, have a slight granularity to them. Pure platinum prints tend to be a neutral grey-black whereas pure palladium prints are very warm, looking like sepia toning. They portray a very long tonal range.

[cliveh]

Trevor, thanks for the description, but although that may help me, being visually orientated to help discern the difference, is there a method that the general public can use in order they are not duped?

[Maris]

Trevor Crone has it right. Because platinotypes, palladiotypes and combinations of the two (the usual) don't use an emulsion on paper the surface texture is the same in image and non-image areas; usually very matte.

These process are made by contact exposure so the characteristic shapes of the negative rebates surround the image. Outside the tell-tale negative rebates there is often a ragged edge where the coating brush has carried the sensitiser beyond the picture area.

If the photograph is edge cropped by an over-matte these "making marks" may be hidden and consistency of texture is the only reliable guide. A good magnifier helps.

[Trevor Crone]

Clive, personally I do not know of a 'sure-fire' way that 'joe-public' could use to see if a print was genuine pt/pd. Other then what Maris points out regarding coating methods beyond the image. However many photographers/print-makers mask or trim these areas off. And sorry to say it but there are some dreadful D methods that simulate the pt/pd print:mad: Also there are some gelatine silver papers that come close to having the 'look' of a pt/pd print; I believe Bergger Prestige Fine Art is one such paper; http://www.linhofstudio.com/products/fineart/papers.html

[Dave Hall]

Thanks to Trevor and Maris. Have often wondered the same topic / issue myself

[Trevor Crone]

These two links may be of help/interest;

http://photo.net/black-and-white-photo-film-processing-forum/00Lynb

http://www.garyauerbach.com/articles/catalyst.pdf

[cliveh]

Trevor and Maris, thanks, that was very informative and the links help a lot. I think I may even add them to my FADU gems folder.

[cliveh]

I am a little confused, as Maris points out there is no emulsion in a platinum print, but the article link posted by Trevor refers to the emulsion layer. Can I take it that this word is generic in comment and a platinum sensitiser is merely a liquid containing metallic salts, as is a van Dyke brown or a salt print applied to the paper surface?

[Andrew F]

I am a little confused, as Maris points out there is no emulsion in a platinum print, but the article link posted by Trevor refers to the emulsion layer. Can I take it that this word is generic in comment and a platinum sensitiser is merely a liquid containing metallic salts, as is a van Dyke brown or a salt print applied to the paper surface?

Yes it is I've attached a link to a youtube video showing the making of a developed out PT/PD print.

http://www.youtube.com/watch?v=U_oKJXhrqXI

[cliveh]

Yes it is I've attached a link to a youtube video showing the making of a developed out PT/PD print.

http://www.youtube.com/watch?v=U_oKJXhrqXI

Andrew, thanks for this, I wouldn't mind having a go. Can someone advise on a simple sensitiser/process chemistry and where I could buy them? I guess it is probably quite pricey.

[Trevor Crone]

Andrew, thanks for this, I wouldn't mind having a go. Can someone advise on a simple sensitiser/process chemistry and where I could buy them? I guess it is probably quite pricey.

Clive, it is a fairly simple process, but alas expensive and as far as I know the Pt/Pd solutions are only available HERE (http://www.bostick-sullivan.com/); ironic when you consider it has a British patent.

I prefer the developing-out method using potassium oxalate as the developer and potassium dichromate to control contrast. Sadly both are very toxic. All chemicals other than the pt/pd can be obtained from Silverprint. For the sensitizer, solution A, I use ferric oxalate and oxalic acid, solution B is the pt salt and solution C is the pd salt. As you know the pt/pd can be mixed depending on 'image look'. I tend to use 2 parts pd for every 1 part pt.

[cliveh]

Trevor, thanks, but wow that is expensive. I would be interested to know how it’s made, as it may be cheaper to obtain a small amount of the metal and make the solution yourself. Any info out there on that?

[Trevor Crone]

Clive, sadly the price of most metals has risen sharply recently and all I can say is be on the look-out for special dealer offers and online auctions, which is what I did and got them a great deal cheaper than they are today.

[cliveh]

Trevor, my thought was that if you bought something like platinum earing studs or such like from second-hand jewellers, you could use the base metal to make up a sensitising solution.

[Trevor Crone]

Clive, you will probably need to dissolve the platinum in aqua regia (conc. hydrochloric and nitric acid) and then add excess potassium chloride so you end up with potassium chloroplatinite. But I don't know the exact process. The sensitizing solution is about 20% pot.chloroplatinite.

[cliveh]

Trevor, I guess it is a question of getting the correct weight of platinum to the correct quantity and molar of acid, before adding the potassium chloride. I will consult with the chemistry experts at my college to find out. If I could suggest a metal weight to acid ratio at a specific molar, it may be useful for some other FADU members.