SF IT8-Created Profile Not Rendering Colors Accurately

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Elektron Volt
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SF IT8-Created Profile Not Rendering Colors Accurately

Postby Elektron Volt » Sat Mar 16, 2013 11:21 pm

I'm scanning some of my family's old photos with my Epson 4990, and I just don't seem to be getting as accurate colors as I expect using the color profile created by Silverfast Ai Studio. In particular, the blues don't look right: borderline dark-blues appear cyan, and other blues look slightly off. Colors seem maybe a sliver too saturated as well. I'm using a Silverfast IT8 target on Kodak Professional Endura paper that I bought in 2009 and I've run the IT8 calibration several times, getting a Delta-E of .8; but, using this profile, the colors in the image file just don't look right when I compare it with the print in my hand.

The part that is confounding, however, is that, if instead use Epson Scan and select the "Color Control" option in the preferences, THAT option actually accurately captures the color and saturation almost perfectly. Even though that preference doesn't have an option to specify the color space, tagging the resulting image file with sRGB renders the colors very close to what I'm seeing in the print. After all the talk about IT8 calibration and how important that is, why is the uncalibrated, untagged scan from Epson Scan outperforming the IT8-calibrated scan from Silverfast? Is this expected behavior?

Take a look at my attached examples (Epson scans on left, Silverfast scans on right). If you look at the attached Comparison 1, which is the starkest example, the Irish dancers' dresses are actually more the bluish color on the left than the outright cyan color on the right--Silverfast is not even close on this one. In Comparison 2, you can see the subtle but clearly noticeable shift in color from blue to cyan in the center woman's dress. Comparison 3 highlights the slight saturation issue, but you can also see the color shift in the blues. In all three examples, I can say without hesitation that, looking at each print in my hand, Epson Scan has captured the actual colors and saturation more accurately.

Don't get me wrong, I really like Silverfast, but if even lowly Epson Scan can see the correct colors, shouldn't Silverfast be able to profile and see them correctly as well? Am I missing something?

Any guidance on this would be appreciated.

[Updated 23 Mar to reduce image sizes for reasonable screen display]
Attachments
Comparison-03.jpg
Comparison-03.jpg (145.19 KiB) Viewed 2708 times
Comparison-02.jpg
Comparison-02.jpg (161.44 KiB) Viewed 2708 times
Comparison-01.jpg
Comparison-01.jpg (127.73 KiB) Viewed 2708 times
Last edited by Elektron Volt on Sat Mar 23, 2013 4:50 pm, edited 1 time in total.

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LSI_Ketelhohn
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Re: SF IT8-Created Profile Not Rendering Colors Accurately

Postby LSI_Ketelhohn » Fri Mar 22, 2013 10:14 am

Dear customer,

Have you tried a different preset for the image auto adjustment or tried setting highlights and shadows manually?
On my calibrated scree there is only a slight difference between the images.
It seems that the highlights are set a little different.

Have you made sure the images use the same colorspace for comparison?


kind regards,
Arne Ketelhohn.

Elektron Volt
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Re: SF IT8-Created Profile Not Rendering Colors Accurately

Postby Elektron Volt » Fri Mar 22, 2013 3:44 pm

Arne--

Thanks for your reply.

Hmm... I, too, have a calibrated monitor, and I can clearly see a distinct color difference, for example, in the lighter blues in the Irish dancers' dresses. Remember, I have the actual, physical print to compare with, so I know my eyes aren't lying. I sent the Irish dancer scans to a friend, and he, too, said that he could see that the blues were different between the two scans.

The thing is this. The Epson Scan "Color Control" option is the only color control option that gets these colors accurate right in the scan itself. If I choose either the "Colorsync" option in Epson Scan and set a source and target space, or use Silverfast with any color option, the blues don't come out right (too much cyan). Even an HDR scan in Silverfast, with no adjustments at all, the blues are off. It's almost as if Colorsync isn't "seeing" the right colors (in this case, the blues) even though they are there. I know they are--Epson Scan's "Color Control" option is clearly "seeing" them.

I've tried different presets, and even an HDR scan, but the blues are still not being "seen" correctly. I could, of course, try to manually adjust the blues, but this just doesn't seem right to me: Silverfast should be seeing acceptably accurate color without me having to adjust the blues on every scan that has blue in it. Am I wrong? As for the color spaces, the Silverfast scan has the sRGB color space embedded; Epson Scan, however, does not embed or tag the file, so I assign the sRGB color space when bringing it into Photoshop, as this is the only color space where the colors look right (the colors come in too saturated when assigning Adobe RGB).

My monitor is calibrated, and my printer is profiled, with the Spyder3 Studio system, and the scanner is profiled with Silverfast Ai Studio 8 with a Silverfast IT8 target from 2009 (which was properly stored). Why aren't any of the calibrated color control options in either scanning software getting good color right off the bat in the scan itself? What am I missing here?

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LSI_Ketelhohn
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Re: SF IT8-Created Profile Not Rendering Colors Accurately

Postby LSI_Ketelhohn » Wed Mar 27, 2013 12:29 pm

Dear customer,

If an HDR scan shows the same colors SilverFast will not be responsible.
The HDR scan contains the unaltered Scanner data.
These images haven't even been rendered to a working color space yet.

Yes I too see a difference in the dancers dresses.
What I meant to say is that it is within a range which could be attributed to a differing colorspace or different Highlights values.

kind regards,
Arne Ketelhohn.

Elektron Volt
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Re: SF IT8-Created Profile Not Rendering Colors Accurately

Postby Elektron Volt » Wed Apr 03, 2013 3:57 pm

Arne--

I did perform HDR scans, and the colors still came out the same. My question is, what is Epson Scan "seeing" that Silverfast is not? Shouldn't both be seeing the same thing in an unprocessed scan? In other words, if I perform no adjustments, why would Silverfast see those colors differently? Clearly my scanner is able to render the blues in question, yet Silverfast keeps translating them to cyan-blue in the output file.

Many of these prints are old and faded, and discerning the colors is sometimes difficult. I can, it is true, use Silverfast's local and global color adjustments to tweak the colors; but I at least need to know Silverfast is properly seeing the colors first that are there. If I can't trust Silverfast to at least give me a scan that's reasonably faithful to the print in my hand, then that makes it more difficult for me to correctly color balance the photo. With Epson Scan, I don't seem to have to take that extra step. Frustrating.

Any ideas what I might be doing wrong here? Or what Silverfast is not properly doing?

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LSI_Ketelhohn
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Re: SF IT8-Created Profile Not Rendering Colors Accurately

Postby LSI_Ketelhohn » Fri Apr 05, 2013 5:08 pm

It might be that Epson Scan does not even provide true raw data from the scanner.

I will forward your case to our support center.
I think I will need a 48 Bit HDR file to evaluate your issue.

kind regards,
Arne Ketelhohn


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