Hi, Working with Synfig Project here <a href="http://synfig.org">http://synfig.org</a> I've been reading the latest discussion about gradient format and I do agree on define the gradient as this: A Color Gradient is a collection of Stop Points with the following information: -Color definition (inlcuded alpha). -Position (between 0 and 1) -Math formula to move from this stop point to the next If there is need of have a separated alpha gradient just replace the Color definition item by the Alpha definition item and add it as optional. The application should know what to do with that Alpha Gradient once loaded. Let's look into each component: *Color definition: it has to include one of the standard of the color definitions (RGB, CMYK, HSV, etc) and all the information needed. Usually all the colors should be defined in the same color model and it (the model specification) should be included in the gradient format if not part of a common standard. * Position: it just can be defined with a real number between [0.0, 1.0] * Math Formula: The agreement of this part is important for the current existing gradients. Most of the applications uses just the linear approaching but to completely agree this item it is needed that, each application that has non linear interpolation between one stop and the other, compare its most complex interpolation system to be sure that it can be emulated by the proposed general formula. Currently Synfig uses Color Gradients with the following approaching: -Color definition: RGBA color -Position: a real number and no interpolation data, just linear interpolation. Here a simple red to black gradient definition for Synfig: <gradient> <color pos="0.000000"> <r>1.000000</r> <g>0.000000</g> 0.000000 <a>1.000000</a> </color> <color pos="1.000000"> <r>0.000000</r> <g>0.000000</g> 0.000000 <a>1.000000</a> </color> </gradient> Greetings Carlos López