Page 1 of 1

Convert from grayscale to sRGB colorspace

Posted: 2015-08-26T13:50:37-07:00
by q3cpma
The tast I'm trying to accomplish isn't extraordinary but i'm failing hard at it. I've seen some forum topics, but their solutions didn't work for me.

Code: Select all

convert -colorspace sRGB -define "colorspace:auto-grayscale=off" -define "png:color-type=6" in.png out.png
Didn't work. Also tried with

Code: Select all

-set "colorspace:auto-grayscale" "false"
Thanks for reading.

Re: Convert from grayscale to sRGB colorspace

Posted: 2015-08-26T14:06:31-07:00
by fmw42
There is no equivalent -define to the -set option. I believe that is only available in current release, IM 6.9.2-0. You do not mention your version of IM nor platform.

Re: Convert from grayscale to sRGB colorspace

Posted: 2015-08-26T14:13:55-07:00
by snibgo
In modern versions of IM, grayscale is already in sRGB colorspace, meaning that it has a complex gamma curve that is roughly gamma=2.2.

What do you really want to do? How do you know you are not already doing it?

Re: Convert from grayscale to sRGB colorspace

Posted: 2015-08-26T15:20:29-07:00
by q3cpma
Sorry, I was using an outdated version. I needed PNG24 output to go with Vapoursynth's IM plugin.

Using

Code: Select all

convert -colorspace sRGB -set "colorspace:auto-grayscale" "false" in.png PNG24:out.png
worked.

Also, it looks like the -define option is listed here.

Re: Convert from grayscale to sRGB colorspace

Posted: 2015-08-26T16:45:19-07:00
by fmw42
q3cpma wrote:Also, it looks like the -define option is listed here.
I recently asked the developer if there was a -define equivalent. He told me no. So I either misunderstood or he has recently added it.

Re: Convert from grayscale to sRGB colorspace

Posted: 2015-08-27T02:50:18-07:00
by q3cpma
Looks like it works too with -define (identify -format '%[colorspace]' out.png gives me sRGB).

Re: Convert from grayscale to sRGB colorspace

Posted: 2015-08-27T14:14:02-07:00
by dlemstra
I recently asked the developer if there was a -define equivalent. He told me no. So I either misunderstood or he has recently added it.
Or he works too much with IM7 :) This did not work in IM7 but does in IM6. We are now investigating how we can fix it in IM7.