Re: Colorchange during jpg->webp conversion
Przemysław Sobala <[email protected]>
| Newsgroups | gmane.comp.video.graphicsmagick.help |
|---|---|
| Message-ID | <CAGKkJorE5p3CmM8awwdp4H4a2GY4EZy-QyDGO50LS83YgovVPw@mail.gmail.com> |
Thanks for responding. I was thinking about applying ICC profile myself, as I want to create images for web and was about to start stripping all the additional metadata. Could you guide me how can I apply an ICC profile to pixels themselves using GraphicsMagic API? -- Best Regards Przemysław Sobala On Tue, May 16, 2017 at 3:27 PM, Bob Friesenhahn < [email protected]> wrote: > On Thu, 11 May 2017, Przemysław Sobala wrote: > > Hi >> I'm using GraphicsMagick 1.3.25 and libwebp 0.5.2 and I've noticed color >> change when converting images from JPG to WEBP, eg.: >> >> gm convert http://d.wpimg.pl/1972545173--1156527689/paulina-sykut.jpg >> gm.webp >> >> Please compare skin color in source jpg and target webp >> (http://pasteboard.co/50Q0V8llI.png). >> FFmpeg that uses the same libwebp doesn't make such noticeable color >> change. >> > > I think that GraphicsMagick and WebP are correctly saving the pixel values > (looks good on an uncorrected display). It seems that you discovered that > the ICC profile is necessary in order to display the image correctly. I > think that there is a pull request for code to save/retrieve ICC profiles > for WebP. > > WebP is primarly intended for small images such as would be displayed in a > web browser and it intends to optimize file size as much as possible. > Given this, adding ICC profiles could significanly bloat the saved file. > Some ICC profiles are over 1MB in size (many ICC profiles are rather small > as yours is only 560 bytes). > > If one is preparing images for web, then it is best to apply the ICC > profile and convert the image to sRGB space. > > Bob > -- > Bob Friesenhahn > [email protected], http://www.simplesystems.org/users/bfriesen/ > GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ > ------------------------------------------------------------ > ------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Graphicsmagick-help mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/graphicsmagick-help > > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Graphicsmagick-help mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/graphicsmagick-help