I've found the various finishes and colourings you can get on leather a constant fascination. While as a general rule most of our stuff is produced in black and brown it's always fun to play with colours, either making the whole item out of a coloured leather or using colour to pick out details such as in the applique satchels.
There's also the fun of putting colour into the leather yourself. While this is more time consuming it allows you to build one offs without having to track down skins in the right colour which can be hostage to the whims of fashion.
My favourite product for playing with these sorts of things is vambraces, in particular ones that have been laser engraved. There are two ways to approach this depending on whether the image is going to be picked out in gold or silver paint or coloured the same as the vambrace.
If the image is to be picked out then the first step is to dye the vambrace the required colour. Once it's dry it needs sealing against moisture. Third step is to apply a laser mask. This gets burnt off by the laser when the pattern is being engraved meaning you can sponge paint into the engraved area while the mask which wasn't burnt away stops the paint getting onto the coloured area of the vambrace. Then it's wait for the paint to dry and wash off the mask. At this point you find out how good a job of sealing and painting(acrylic paint forms a seal) you did as any gaps will allow water in which wets the leather and can cause watermarks as it drys. I normally back these engraved vambraces off with a calf suede liner as it neatens everything up and adds some depth to the look. Then it's back to the sealant to seal all the stitch holes you've just put in it.
If it's the same colour then it's pretty simple, burn the image onto raw leather then stain the whole thing. Again it's all got to be sealed and if it's being backed off with calf suede, sealed again after stitching.
I have tried something different recently for the same colour stuff. After engraving and staining I didn't seal it with the normal sealant but ironed a wax finish in. In the engraved areas where the top grain has been burnt off it was penetrating all the way through the leather so I'm fairly sure it's going to be sealed against moisture. It's a wonderfully messy procedure especially when waxing the stitch holes but creates a deep lustre to the leather making it worth the chaos.
Next up, I need devise some way of combining the wax finishing with colouring the engraving but that's going to have to wait for another day.