Colour accuracy

[Shrievelty]

When I open an image in AfterShot the colours are not accurate until I make a tone curve (see image attached).

For comparison: in the DxO 6 which I have, the image is correct first time and does not need any adjustment (when set on 'realistic color').

Is there a similar setting in AfterShot?

[afx]

If posting an issue like this, it helps to mention the camera...

cheers
afx

[Shrievelty]

I am happy to mention the camera, a Canon S110, but I do not see why that is relevant. Corel includes it in the list of cameras for which it has created a profile, so I am puzzled why the output needs any adjustment.

[afx]

I am happy to mention the camera, a Canon S110, but I do not see why that is relevant. Corel includes it in the list of cameras for which it has created a profile, so I am puzzled why the output needs any adjustment.

The camera type is all important as every camera is profiled individually and not all profiles are perfect.

If your issue would be on all cams, it would have been noticed already...

cheers
afx

[Shrievelty]

Thanks for explaining, afk.

I wonder how many people check the accuracy of Corel's camera profiles.

[afx]

If you want true accuracy, you will need to profile yourself anyway., rarely anyone does this as typically true accuracy is not required but a pleasing look whatever that is for the user.

cheers
afx

[Shrievelty]

What you say sounds very consistent with my experience.

I can make a profile of my own, using Profile Mechanic. That corrects a Tif or a Jpg. I understand that making a true profile whch corrects RAW is very laborious or expensive so I have not gone very far down that road.

I would upgrade to the latest DxO 9, which supports my Canon S110 and produces an accurate result first time - except that it does not quite because DxO has changed its 'realistic color' setting. The highlights are now purposely compressed, so that users can switch from other settings without having to adjust the exposure and finding that the highlights are clipped. This is such a waste! I have reported it to DxO with lengthy email exchanges, but they are not interested in offering the correct 'realistic color' again. I suppose it is good enough for product photographers, but it is useless for people like me, who want to photograph paintings accurately.

The free RawTherapee is better in that, once you have set it up, it will produce colour-accurate photographs right first time. The drawback here is that it is a fiddly programme to use, and the camera profile itself is not as accurate as DxO's, nor as AS's . (The AS profile is very accurate - once the tone curve has been applied as in my previous attachment).

It is strange that so many programme manufacturers clearly make excellent camera profiles, but then do not let the user gain access to them in the simplest way - getting accurate colours when copying a painting.

[afx]

If you know how to profile, then you can try with AS as well, have a look at the color management tool.
The description here works as well for AS apart from one AS bug:
https://encrypted.pcode.nl/blog/2010/06 ... profiling/
You need to boost exposure in AS before generating the TIFF because of a simplistic error that Dave made in the B5 days which was not yet fixed.

This will not include the fine tuning that is often done by the lab, but depending on your situation might still be better than the canned profile.

cheers
afx

[Shrievelty]

That looks great, afk. You are a mine of information!

I shall look forward to reading it properly, but at first glance the whole operation looks pretty daunting.

I used to make by own profiles with Profile Mechanic, but these were essentially colour adjustements to be applied after RAW processing. The beauty of DxO 6 was that I could get accurate results without spending any more time than was needed to process a RAW image normally. I can hardly believe I have to go to put in all that effort to replicate steps that the programme manufacturers have already taken, and probably better than I could myself.

I am beginning to feel that I should just save my own tone curve as a preset and apply it each time I process a RAW photo. Not ideal, but would involve no more work than I have done already.

However I shall look forward to reading the page on your link more closely - it looks very clear and helpful. Many thanks!

[Shrievelty]

Here is a comparison which may be of interest to anyone reading this thread.

I processed a file from my Canon 350D. This comes out right first time in DxO 6.

In CorelAfterShot it required an adjustment to the tone curve. Then the result was very good (attached).

I notice that the tone curve correction is similar to the one I needed for my Canon S110, though not exactly the same.