I've taken the liberty of changing the subject line as we seem to have departed from the original topic. Hope this is OK.
On Tue, 10 Feb 2004 15:48:33 +0000 Richard Kenward wrote: > Subject: Re: [PRODIG] Canvas style papers for Lyson Fotonic Inks > > .......the problem is I am looking for big file sizes for this > application and this means scan back. Richard - I'm assuming your interest is based on reproduction of paintings which I know is one of your interests. In the research lab (Vasari Project, then IBM Pro 3000 system) the file size problem was dealt with by having a tracking device, then stitching pictures. Other research has found that there is a delta E variation of up to 2 (from memory) between the optical centre of the lens field and the periphery on, as I remember, a 1 metre picture. > > A print can 'fade' quite a lot before the human visual > >system can detect it. A colour difference of less than 2 delta E is > >considered imperceptible, > I believe that deltaE 1 is the smallest difference that most people can > detect, however if it's a colour change in a neutral it comes right down > to .5! Not disagreeing, my reference was for the observation of pictorial subjects, but if its convenient do you have a reference I can follow for this for my information? > >I sell fine art prints through an art gallery, so am pretty concerned about what I say to customers about longevity. > Do your customers ask...not that I am suggesting you shouldn't inform > them<G> The informed art collector who buys limited edition prints does ask, yes. In the UK we seem to be following an American trend of growth in the collecting of photography inkjet lim ed prints, particularly b/w. What is more common with my average buyer is for someone to ask why they are so 'expensive'. So I end up explaining acid-free papers and pigment longevity. > >I know he sticks prints on the window to see if they fade as well as having Wilhelm tests done! > > That's the way I do it. Have a known control and base the results > against that....a real world test but totally unscientific, but then > customers don't display prints in some test lab do they and the customer > is king/queen<G> Well yes, except that the test lab gets the most accurate results, so surely there is a lot to learn from their methodology. A major problem is that some pigments reproduce fine, others really poorly, depending on how closely the ccd filtration matches the cone response. My gallery artist/partner copies large painting sections on his Umax A3 flatbed, then stitches. With pink/red poppies, I honestly can't see the difference, and I've been looking at images analytically for half a century! (guess my cornea must be pretty yellowed by now). But if an artist has used cobalt blue, its a different story (combination of IR reflection turning blue purple, and a 'hooking' of what should be a linear response in the Lab colour appearance model). Tony Riley (Kendal) www.photosightdesign.co.uk www.sharpedgegallery.co.uk =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
