hi all forgive me as I’m new and struggling a to get my head around darktable, first day using RAW editing software.
I’ve got some product shots that are shot on a white background but it needs to be 100% pure white for the website.
My idea is to isolate the area around the product using the path tool and bump the exposure to 3.00 EV, but the area not being selected is going dark - see linked image.
can someone advise the best way from getting the background to white? Thanks!
I think you need to invert your mask. Click the circle with the cross inside it, located to the right of “1 shape used.”
thanks for the reply, but it’s the outside are I want lightened. the screenshot below has the exposure toggle on, showing it’s the outside area being changed but, the darkness over the cushion is also added. It’s this darkness I don’t want added to the pic.
image prior to the change:
https://photos.app.goo.gl/wqxvFtXDQNK6wZzQA
showing the areas that will be over exposed:
https://photos.app.goo.gl/sxyUaiPXYiQtMMxy7
after it’s been applied - why does the cushion area go darker?:
https://photos.app.goo.gl/pe9UyZhB9wFrbWJh9
ok, I think I know the problem, I’m trying to apply the exposure twice and the initial eposure change is being lost.
Steps:
1 - exposure : uniformly once to generally brighten the entire image so the cushions are bright enough
2 - exposure : just the white background via drawn mask
the 2nd step is removing the 1st step!
is there another way to achieve this? brighten exposure of entire image and set background to pure white?
Use the tone curve and pull it upwards.
I would use a drawn¶metric mask, limiting the input’s range to the bright part. This can even make the drawn mask (as seen above) unnecessary. Worth a try.
Did you create a new exposure instance? I’m f not, the second exposure settings overrides the first settings. In the history stack you can see both but only the last will be effective …
Hi @buckerooni and welcome!
No need to apologize 
darktable can be quite a mouthful to learn.
If you could upload a RAW file I am sure that you
would get some good ideas on how to go on…
Have fun!
Claes in Lund, Sweden
ah. thanks, didn’t realise you could have more than one instance , makes sense and solves this initial problem.
2nd exposure instance - using drawn & parametric mask and bumping the EV:
https://photos.app.goo.gl/qnJrjhWntgSdc4up7
afterwards:
https://photos.app.goo.gl/jAUhPVDCJa6YVNMB6
what’s the best way to get rid of the pinky shadow? Is adjusting the EV the correct thing to do, or is there something else?
thanks
Thanks Claes, here’s the link, I’ve taken better exposed pics since then, but to keep it consistent with my post here it is.
As i’ve got to do around 40 shots with this treatment (getting the background white) I’m after a fast way to do it. I also use GIMP so i can do any final cleanups there too.
you mean like this? on tone curve, added a drawn¶metric mask (to take the cushions out of it) , messed around with feathering and then lifted the curve.
https://photos.app.goo.gl/JoputJ75UdcCaEJV7
it turned out pretty well!
https://photos.app.goo.gl/zW8x6oiKKqC5Soat5
any other suggestions?
hi there, thanks for the suggestion, do you mean like this - in exposure - changing the input settings like this - without masking I’m still picking up alot from the cushions.
I don’t do product photography, but I know it’s important to get your colors as accurate as possible. So what I did was boost the saturation and contrast to simulate your “correct” colors. Then using the tone curve, applied a drawn mask around the edges with a fairly wide feathering and then inverted it. Then I boosted the tone curve plenty. I thought that the “screen” blend mode produced a better result than “normal.” Then I retouched the colored areas that ought to have been white. Hope this helps!
@buckerooni You have mentioned GIMP. Wondering why you would do this step in dt rather than in GIMP. I am guessing that you would like to do everything in dt, is that right?
Hi @buckerooni ,
With the parametric mask, you can select not only the areas of brightness, but also the color channels, hue and saturation.
In this case - I used curves here - reduction of green and yellow has improved the mask a lot:
You should also play with feathering radius, mask blur and mask contrast to make the mask even more precise:
At the end you need additional inverted drawn mask only for the pillow:
Result:
hi, happy to use GIMP if its the faster tool with the same result. I’m making an assumption that any colour/shadow corrections will be better in darktable, as working on a compressed image in GIMP will not be as sharp?
my thinking was, the closer I get to white in darktable, the less I have to do in GIMP, and the less likely I have to do another roundtrip to darktable.
if my assumptions are wrong, let me know!
Wanting to do it in dt isn’t a problem. Just wanted to know the reason behind your question. 
Personally, I would do the raw development in dt (focusing on making the product look the best it can) and then do the rest in GIMP (removing or replacing the background, adding a logo or watermark, etc.). The newest GIMP allows you to do edits in a colour managed, high bit depth environment, and it has a great set of tools, but that is for another thread…
thanks everyone, it’s been really helpful, images looking better already!
thanks for this, I will check this out, looks like I’ll have to boost my skills to replicate this one!
