To achieve this tyedye/ galactic effect I used eco flo dyes and a sea sponge. Working in stages with one color at a time I layered 3 primary colors to achieve this effect. I went yellow then red, then blue in order. Also I layered yellow heaviest , red medium, and blue light-medium to gain the overlapping color mixing effect without just making brown.
To get best results you have to make sure dye is evenly distributed on the sponge and press gently without smearing. You have to go up and down but only move it sideways when not touching the leather.
Also it really looks quite amazing once it’s sealed, so don’t be discouraged if the colors don’t pop as much as you would like at first.
I find it easier to do a large panel that I can cut up to size for the other pieces I need to make. I used this for the 2 main compartment panels, the shoulder straps, and side pocket straps.