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Author Topic: Whites on Non-OBA Paper?  (Read 1924 times)

gfabbri

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Whites on Non-OBA Paper?
« on: March 29, 2010, 08:36:38 pm »

I'm just curious if profiles for natural rag papers attempt to compensate for their warmth to produce truly neutral whites & grays, or whether the warm tonality of these papers effectively shifts the white balance of images printed on them. From my very limited experience, I perceive whites printed on natural/warm papers as "whiter" than the paper white, but this could totally be a visual illusion...

Just wondering...

-Gian
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Brian Gilkes

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Whites on Non-OBA Paper?
« Reply #1 on: March 29, 2010, 09:49:11 pm »

It depends on the profile. The white point should be allowed for , of course. The trick is to to allow correctly for the paper colour in linearising the luminosity. Most profiles , including custom profiles , do not do a very good job of this. If done correctly the white may look whiter than the paper. This will be aided by the adjacency effect; a darker tone around a light tone makes the lighter tone look lighter. A luminosity corrected profile makes it look "correct". Everything we see is an illusion. Beautiful profiles enable compatible illusions.
Cheers,
Brian


www.pharoseditions.com.au
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gfabbri

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Whites on Non-OBA Paper?
« Reply #2 on: March 29, 2010, 09:54:54 pm »

Quote from: Brian Gilkes
Beautiful profiles enable compatible illusions.

Very poetic... thanks, Brian, for the reply!

-Gian
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Ernst Dinkla

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Whites on Non-OBA Paper?
« Reply #3 on: March 30, 2010, 07:08:19 am »

Quote from: gfabbri
I'm just curious if profiles for natural rag papers attempt to compensate for their warmth to produce truly neutral whites & grays, or whether the warm tonality of these papers effectively shifts the white balance of images printed on them. From my very limited experience, I perceive whites printed on natural/warm papers as "whiter" than the paper white, but this could totally be a visual illusion...

Just wondering...

-Gian

Gian,


As long as there is no white ink in your inkset the only compensation for warm papers possible would be neutralising with complementary hues: cyan, green, ink.
Depending on your profile creator that could be a choice but usually is not done down to the RGB 255,255,255 value. If done it would make a more neutral white but with a lower reflectance than the unprinted white. So what you observe will be a visual illusion.

Use a loupe to see whether there are cyan dots in the white. If there are cyan dots there it may even be a flaw in the profile creation if you are working with a combination of Epson, Adobe, Apple components. As I understand it that shift should be visible without a loupe.



met vriendelijke groeten, Ernst Dinkla

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/

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