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Image color shift in EMu display?

Image color shift in EMu display?

Hi everyone, we are trying to figure out why some of our images appear differently when imported into emu than they do when we finish preparing the files in Photoshop. We know the appearance change is not just in emu; it also happens in various other image viewers such as Windows Picture and Fax Viewer, Quicktime PictureViewer, Microsoft Paint, and so on.

Our working theory is that all of the applications where the appearance changes are not "color-management-aware". But we would like to understand what is going on in case we need to tweak our image editing workflow.

All of the images we load into emu are jpegs derived from master TIFFs. The TIFFs are color-corrected in the Adobe RGB (1998) color space. When the jpegs are created, we embed the sRGB color profile, with the rationale that sRGB is sort of the safe, standard, internet default, lowest-common-denominator, color space. We have thought that embedding the sRGB profile should prevent any really weird appearance changes like we have observed when a non-color aware application tries to display an image with a color profile like Adobe RGB (1998).

We know that this is strictly a display issue, because when we take the image round-trip from Photoshop to emu and then save it out of emu and open it again in Photoshop, the original Photoshop appearance is unchanged.

We tried several variations, including saving the jpeg with no color management at all, converting the profile rather than assigning it, etc., and the same thing happened.

Does anyone know what emu is doing when displaying an image that might explain this? Any other ideas of what we should be investigating?

Edited by: - 01-Jan-70 09:00:00

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Re: Image color shift in EMu display?

Hi,
Here's some feedback that may help- (sourced from a reputable digital imaging scholar).
All the applications mentioned are simply not colour savvy - that is they do not have any means of interpreting the embedded profile, therefore they are not colour managed, so you can not expect to see the same colour on screen as you would when viewing the same image in a colour managed application like Photoshop. It is no more complicated than that. In other words, the vast majority of applications on Macs and PCs are not colour savvy, so we can not trust the colour they display even on a calibrated monitor, because they have no way of transforming the image's RGB numbers to those required by the monitor's profile so as to be able to display correct(ed) colour on screen.

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Re: Image color shift in EMu display?

I have seen this happen to a few multimedia records created from jpegs from a low spec digital camera. The images view normally in Microsoft image viewer but not in thumbnail view in eMu. Google's picassa also displays the images in a strange RGB colours.

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Re: Image color shift in EMu display?

So following on from this, the new Multimedia Web Service released with EMu 4.0.03 allows generation of derivs on the fly.

This could be a fantastic efficiency tool, but we'd need to be sure the generated derivatives are colour accurate. If not, it's not even worth looking at.

Has anyone tested this yet?

Mark Bradley – Assistant Registrar, Documentation (EMu)
National Gallery of Australia

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Re: Image color shift in EMu display?

Nobody?

Mark Bradley – Assistant Registrar, Documentation (EMu)
National Gallery of Australia

Mark Bradley
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