The toner idea is very cleverly conceived and implemented.
Sent from my iPhone
On Jul 9, 2015, at 10:50, Paul Roark roark.paul@... [DigitalBlackandWhiteThePrint] <DigitalBlackandWhiteThePrint@yahoogroups.com> wrote:I suspect there are differences among the various LED lights, but presumably your local art museum bought some with a reasonable CRI (Color Rendering Index). None of the LED CRI's that I've seen can match a Halogen  light, however. ÂIn side-by-side viewing, you can see a one unit Lab B difference -- barely. My original variable tone inkset was made so that I could show my digital prints in a mixed show with the silver prints. I don't do that any more, but the variable tone approach is still a good way to go, giving you the option of your 100% carbon while also having the toner there when needed to help match cooler prints. If you're using a 1430, take a look at http://www.paulroark.com/BW-Info/Eboni-Variable-Tone.pdf .I have the toner in fade testing now. Nothing is going to be as stable as your 100% carbon pigment prints, but this Canon Lucia EX based toner ought to keep the color shifts to a minimum. Since the pigments used are now both from the same Canon inkset, the http://www.aardenburg-imaging.com/ fade test of that inkset is going to give a better idea of the degree of shift. There is a patch in Mark's testing that has a very similar Lab A and B to the toner. In the last paragraph on page 5 of http://paulroark.com/BW-Info/3880-Eboni-Variable-Tone.pdf I've done some calculations as to expected color drift. While I'm waiting for actual test data, the calculations based on Mark's work suggest the color drift will be well below the visible limits at 50 "Wilhelm years" of display.BTW, where the carbon prints you displayed the original Eboni or Eboni v. 1.1?PaulOn Thu, Jul 9, 2015 at 6:43 AM, paulmwhiting@... [DigitalBlackandWhiteThePrint] <DigitalBlackandWhiteThePrint@yahoogroups.com>; wrote:ÂFor years I settled on darkroom prints using Ilford MG paper and Bainbridge Spanish White mat board. Under gallery lighting they looked great - I must have been showing under tungsten lighting. Then, as I moved to digital printing, I settled on carbon ink, Eboni to be exact, on Premier Art Fine Art paper in the 205 gsm weight. I mounted these prints on a slighter warmer board, Crescent #2299. Displaying these two kinds of prints side by side I could hardly tell the difference.
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But a couple of days ago I was doing a small show at our local art museum and they had just switched to LED lighting. The darkroom prints looked fine, but my digital prints were decidedly warmer. Not much I can do about this... I think I'll have to live with this conundrum. Perhaps some of you have run into something similar. Gradually, as I sell my darkroom prints, I'll be reprinting on the digital setup and my shows will have more consistency. But I really am not fond of how they look. Maybe I'll have to move to a different printer inkset and a cooler mat board.
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At home, and in clients' homes, this is not a problem for the time being. I suppose as our society gradually switches over to LED lighting I'll be up against this dilemma more and more. I notice LED lamps are hitting my local hardware store.
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Any thoughts, advice, feedback would be most welcome... thank you!
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Paul
Message
Re: [Digital BW] LED lighting in art gallery - some issues
2015-07-09 by Paul Roark
Note that the toner formula that the 3880 uses has a higher concentration of the Canon pigments than the version I used for the earlier 1430 and 7800 setups. The reasons include that the higher concentration allows the ABW mode printing of the 3880 to have at least some range. At least one paper can go from carbon warm to a delta-Lab B of 2 (that is, a maximum Lab B that is only 2 units over the paper base Lab B value), which many will see as neutral when not next to brightened paper or a cold toned paper. Also, it turns out that the higher concentration, which is still essentially the same density as the lightest carbon ink in the mix, does not show up as visible dots. Finally, (and frankly) the very dilute mix would have allowed a certain commercial seller to still make a profit at a low 4 oz. bottle price, but since that commercial outfit showed no interest, other factors became more important.
Paul
On Thu, Jul 9, 2015 at 12:48 PM, 'Dr. Elliot Puritz' drpuritz@... [DigitalBlackandWhiteThePrint] <DigitalBlackandWhiteThePrint@yahoogroups.com> wrote: