How to create a raw tone curve to match default jpeg from camera?

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How to create a raw tone curve to match default jpeg from camera?

Thanks for keeping this fantastic program alive!

When following the instructions in the Wiki - "Creating Raw Tone Curves" for my Pentax K5 using images from Imaging Resources I end up with a raw tone curve which gives me a very low contrast result. Of course it is easy to work on this and modify the contrast to my liking. But a raw tone curve matching the default camera settings would probably be a starting point closer to what I want.

Is it possible to measure both the jpeg file from Imaging Resource and the raw file and by some procedure create a tone curve matching the default jpeg from the camera?

Not that we know of---and if

Not that we know of---and if you find one let us know!

Seriously, matching default jpg's can be extremely challenging in any program, I think (although I haven't tried it for years, and I've never tried it with camera manufacturer's software).  I used to try to match my Oly jpg's---Oly used to have arguably the best in the industry---but i finally gave up after having a personal epiphany about my images.

IMO, and I think in the opinion of a lot of dedicated raw shooters/post processors, a "dull", low contrast raw is music to our eyes.  We want that because we want to have lots of room for manoeuver for the processing we want to apply. Having things already contrasty means having to be a lot more careful.

That said, we encourage experimentation by the user community.  By playing around with various options users should be able to find the combination of contrast and sharpening (another form of contrast) and saturation changes that together give an approximation of the default jpg.  That tool stack can then be easily saved as a style and applied to a whole file of raw images through batch processing right out of the browser.


Thanks alot for your reply!

I agree that a low contrast picture is a good starting point.

Anyhow if I want to make a profile matching the default in camera profile i hoped that by using the same procedure as described in the Wiki reading off the luminosity values from the color checker for the jpeg and somehow putting those values into the ruby script and then reading off the lumnosity values for the raw file and running the script and by some magic a perfect tone curve would emerge.

I tried by just reading off the values from the jpeg file and substituting the "target" values inside the script with the new values, but that did not work. It gave a tone curve wich was approximately two stops to light.

Do you think it is at all possible to use such an approach to get to a usable tone curve?


I just don't know---never

I just don't know---never tried that. Sounds plausible, but maybe there is some technical hurdle? 

I decided to stop trying to match jpg output when I failed to match those Oly jpg's after much work---and then wondered to myself why, as a trained artist with decades of personal work across several media behind me, I was trying to match what some Japanese software engineer thought made for a good looking image.  I never tried again.  When I'm doing family snaps and quick things for personal life documentation i just go ahead and use jpg out put right up front.  For anything remotely serious I use raw and then work on it so that it looks the way I want it to w/o regard for anyone else's input. As an artist, I trust my training and vision.

more primitive approach

I managed to create raw tone curve for my cameras following Dougs instructions in this video

It is possible to get very similar results to out of camera jpeg you just need some patience. Just use luminosity values from your jpeg shot of color checker, I think you'll be able to do it very quickly.

Color signature, on the other hand, is a very different story and I never managed to achieve very good match to Olympus jpeg.

Good suggestion!

Primitiv but efficient. I was also able to make a OK match to my Pentax K5. Thanks a lot for your suggestion.

I did some testing with the other aproach and as you say the in camera tone curves are different for different colors. So i guess I would need to reed up on the theory to be able to make any progress. And I think I rather would do some photography :-) And as tex suggest the built in raw curve is just what some software engineer thought made a good looking image. So I think I just use the manually created curve as a starting point.