# Libpng errors

## Problem

Some changes in libpng 1.6+ cause it issue warning or even not work correctly with the original HP/MS sRGB profile. You will notice this in stderr:

    libpng warning: iCCP: known incorrect sRGB profile

The old profile uses a D50 whitepoint, where D65 is standard. This profile is not uncommon, being used by Adobe Photoshop, although it was not embedded into images by default.

## Solution

The simplest solution is simply to remove the embedded profile from your image. This can cause a slight shift in color *IF* have have a properly calibrated system, monitor, and software. If you really need it (say for a print shop), you can alternatively embed a different color profile. If this applies to you, you probably have the profiles you need already.

### GIMP

  To remove the embedded profile, go to `Image > Mode > Assign Color Profile` and set it to `RGB workspace(sRGB built-in)`
  To change the embedded profile, go to `Image > Mode > Convert to Color Profile` where you can choose a profile you already have loaded or load a new one from disk.

### ImageMagick

  To remove the embedded profile, just run `% convert -strip <input filename> <output filename>`

Category:

- Image manipulation