Datacolor User to User Support Group.

Have you turned off BPC?

C. D. Tobie
WW Product Technology Mngr.
Digital Imaging & Home Theater
DataColor.com
CDTobie@...

On Jul 24, 2008, at 4:52 PM, "marko.mili" <marko.mili@...> wrote:

> This is an old thread, but my question ties into it. I have been
> trying to profile Canon iP4500 and iP4300 printers, with both OEM and
> Image Specialists inks. It quickly becomes obvious that these printers
> suffer in reproduction of dark saturated colors, especially reds and
> to lesser degree greens. Not so bad in yellows and blues. With OEM
> profiles, the way Canon gets around this is by having perceptual
> rendering quite a bit lighter then actual colors, which brings dark
> colors into gamut. This is just eyeballing soft proofs and a few
> output samples. I don't know really if Canon does this with images
> when all colors are in gamut. These printers suck and most images have
> plenty out of gamut. The main difference is in how OEM and Colorvision
> differ in perceptual intent, with OEM being about a stop too light.
> Other intents look about the same between OEM and Colorvision.
>
> The end result of this, due to how poorly these printers render dark
> saturated reds and browns is that none of intents made by Colorvision
> look photographically natural. Not that colors don't match source, but
> relationships between colors look unnatural. For example, if someone
> is wearing a red sweater, in folds of the fabric where red is in a
> shadow, it looks weirdly brown/grayish in all intents (some more some
> less, but none satisfactory). With OEM perceptual, all colors are
> wrong (mainly in that they are too light, but also in hue and
> saturation), but at least they preserve relationship between colors
> and it looks believable.
>
> I would suggest that Colorvision perceptual rendering shouldn't match
> on just hue and brightness and ignore saturation (if that is how it
> works, although I suspect that explanation given below is simplified).
>
> In a difficult situation at least the way OEM perceptual works is
> effective. How can similar results be achieved with Colorvision
> profiles, without bringing each image into gamut by hand (which is
> fine for exhibition, but not when I want to print 100 vacation
> snapshots for my mom)?
>
> Marko
>
> --- In colorvision_group@yahoogroups.com, CDTobie@... wrote:
>>
>>
>> In a message dated 11/14/07 12:31:47 PM, ryannd@... writes:
>>
>>
>>> On the profile I made with PrintFixPro the bright yellows
>>> (especially around the sun in the sunset picture at the lower left
>>> but all yellows in other parts too) are muddy and have lots of black
>>> in them on perceptual and look good on saturation intent. And the
>>> prints look just like the soft proof--unusably muddy on the yellow
>>> colors with perceptual rendering.
>>>
>>> You guys off course recomend saturation and not perceptual intent on
>>> rendering and that works fine for CS3.  Unfortunately I do almost
>>> all my printing with Lightroom which doesn't give me a choice of
>>> saturation -- it's perceptual or relative only as rendering intent
>>> with Lightroom.
>>>
>>> Help!
>>>
>>
>> In one sense, this is a Lightroom issue, in that they do not support
> the full
>> list of intents. What is happening is that you are asking for out of
> gamut
>> yellows, and the match is being selected based by Hue and
> Brightness, without an
>> emphasis on Saturation, in our Perceptual intent. The color with the
> closest
>> density and hue angle does not suit you. Between now and the next
> major update
>> to Spyder3Print, there will not be any changes to our color engine,
> so what
>> you get is what you get, for the time being. This is only one of
> several
>> reasons I don't print from Lightroom.
>>
>> On the other hand, the test images you note are filled with
> oversaturated
>> colors, colors that you don't actually find in photos, only in
> vector images and
>> heavily adjusted images. This test image has lots of yellows that
> hit 255 red,
>> and well over 200 green in AdobeRGB. Not colors you're likely to
> bump into
>> with actual images. So be sure this problem is a problem for your
> own files
>> before you panic, based on this over-the-top test image. Don't judge
> the
>> "reasonableness" of these test image yellows by looking at them on
> your monitor. They
>> are all outside the gamut of a typical display; most are also
> outside the gamut
>> of a Wide Gamut Eizo display...
>
>
>
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