JPG to RAW color profile compatibility

Topaz Products Product Technical Support
1

I started the trial of the JPEG to RAW AI application. It seems, there is no option to use other than ProPhoto color profile. Unfortunately, several RAW handling application unable to open under this circumstance. Would it be possible to add an option to choose output color profile as sRGB, AdobeRGB and ProPhoto - same as in Gigapixel ?

Endre

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2

I don’t believe GigaPixel AI allows you to use a profile for DNG’s.

3

Proper ex camera RAW images don’t have an assigned color profile to limit colors into a specific gamut. Now I know the DNG exported from JPG to RAW AI is not the same as an ex camera RAW file, but in keeping with proper raw files, it doesn’t have an embedded color profile.

The TIFF exported from JPG to RAW on the other hand does have an embedded color profile and in keeping with its 16 bit (48 bit) depth that profile is set to ProPhoto to give the widest common gamut.

I’m not sure why one would want to use JPG to RAW to convert a JPG to a TIFF, as that can be done in any editing program.

When the DNG produced from JPG to RAW AI is subsequently edited, one would expect to select a suitable color profile to be embedded in the exported file. Given the the gamut in the original JPG may have been restricted by an embedded sRGB color profile, I wonder whether that gamut has actually been widened, or to what extent it has been widened, by the conversion, and whether the range of colors actually in the image does fully cover the normal gamut expected by say ProPhoto.

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4

JPEG to RAW doesn’t just convert a JPEG to DNG but will correct artifacts, restore dynamic range, and recover detail as it is highly effective at removing compression artifacts and recovering color detail. It will also enhance dynamic range as shown by deeper shadows and enhanced highlights.

If you want a description of what a Linear DNG is see it here, it is NOT a RAW DNG:

If you want a copy of the ProPhotoRGB ICC profile download from the internet, specifically chromasoft - ICM Profiles. If you are on Windows just click on the profile in explorer and select install.

5

Hi Greyfox,

Thanks your comment. Thinking more deeply to the color profile importance, I have to confess: you are right. A RAW file doesn’t necessary to have any color space definition. It is true, some DNG file including color space info sRGB or Adobe RGB, but it is not so useful.
I sent a sample image to RAW Digger app. It seems the Topaz application stitch the histogram to the max white values of the image right .

image
image1335Ă—1038 1010 KB

Here is the original JPG
image
image933Ă—650 561 KB

It seems the conversion make a normalization process too. Do you think, it is suitable for RAW images ? In my practice, the headroom on the top of the histogram allow to edit the images more freely. The main reason to convert JPG images to RAW is to adjust more parameter. E.g. the DxO PhotoLab doesn’t apply better noise reduction and white balance adjustments for JPG images.
Anyhow, I agree, this app is useful to improve several JPG images quality with 3rd party application. Unfortunately, it generates DNG files with less compatibility e.g. with DxO Photolab it is not compatible, meanwhile the ACR open it poerfectly.

Endre

6

You are right, RAW files doesn’t have such parameter. Sorry.

7

Thanks for the information and the link to Joe’s description of Linear DNG.