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Old Aug 12, 2003, 7:41 AM   #11
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i've got prints from the 1930s range and slides from the 50s too. in boxes that were in cool dry places.

up until recently i could not find a inkjet ink stable enough to call archival. the 2200 is pretty close though. there already is a substantial difference in the lasting quality of the images under direct sunlight. there is a world of difference between dyes and pigments. the mention color gamut is true on the dyes but is much wider in the pigments now. the issue with the pigment now is metamerism or how some colors look under different light sources.
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Old Aug 12, 2003, 10:10 AM   #12
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Originally Posted by sjms
i've got prints from the 1930s range and slides from the 50s too.
Are these *colour* prints from the 1930s? If so, what sort of chemistry did they use? They've done astonishingly well to last that long. If we have our digicam images photoprinted using conventional silver halide chemistry, it'll be much better than common-or-garden inkjet prints, but we shouldn't kid ourselves that they're permanent.

Loss of long-term permanence was the one huge leap backwards when mass market colour photography supplanted black & white in the 1960s. I've just been working on the photographic material for my septuagenarian in-laws' memoirs. Their 1930s b&w prints are perfect, and their 1960s Kodachrome slides are fine, if a little mouldy and dusty. Many of their colour prints are faded, despite being shut in albums for 30-odd years.

All the common colour photographic processes except Kodachrome slides and Cibachrome prints use dyes that are not as permanent as we'd like, though they are much better than ordinary inkjet inks.

The common chemistries, such as C41 for prints, E6 for slides, and ordinary colour print papers, all have the dyes synthesised not in a chemical factory, but in situ in the emulsion during processing. 'Colour coupler' molecules in the emulsion plus the oxidation product of the colour developer link together to give a long molecule with the desired colour. This is a remarkably clever bit of chemistry.

In contrast, in Kodachrome and Cibachrome processes the dye molecules are presynthesised in one piece. In Kodachrome they are diffused into the emulsion during processing, and in Cibachrome, the unwanted dyes are selectively bleached out during processing. It is thus inherently easier in these latter processes to use permanent dyes; the colour chemists have fewer constraints because they don't have to meet the requirements of developer chemistry as well as everything else.

So the only things that are fairly permanent are our digital data, *provided* that we remember rigorously to transfer to each new digital storage medium as it comes along.

I wonder why it's so hard to make cheap, permanent inkjet inks? Perhaps it's the temperature tolerance? Any experts around to enlighten us?
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Old Aug 12, 2003, 10:17 AM   #13
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no b/w. sorry i did not realize that one would not assume this due to the timeline predating color chemistry. but then there were those colorized hand colored ones.

and to add on there UV and good old Sol puts out lots of it. then most flourescent lamps put out a good bit too depending on the wavelength filtering in the tube.

in Kchrome there is also more silver left after processing thus adding to the longevity.
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Old Aug 12, 2003, 11:35 AM   #14
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I wonder why it's so hard to make cheap, permanent inkjet inks? Perhaps it's the temperature tolerance? Any experts around to enlighten us?
I'm no expert, but think about the background to inkjet printers. They come from a need to print black and white typed output first, then colour pc graphics and now photo printing. I'm sure permanency wasn't at the top of the list when consumers were screaming for more resolution.

Now we all remember fixing our prints with Hypo and what a good job it did. Right from the start, keeping the halide image was integral to the chemical process. That's one thing about laser toner, the colorimetry is poor, but the thermal melt of the polymer probably makes for long lasting hard copy.

Anybody got any thought on life of dyesub prints?
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