Hello
As a new member, I am not quite sure if this is the right place, but....
First off, let me start with a bit of a background info. I am by no means a professional leatherworker. My day job is prop making / replicating for films, theaters, reenactors etc. This includes doing some work on leather every now and then (wish I could do it for a living though). For past 4 years I've used the same supplier of leather and other leather working products just fine. But yesterday I ran into a problem I haven't faced ever before.
As you can see from the attached picture, I was in the process of making some leather items for a project and moved on to dyeing the leather. Previously I have gotten desired results with just slapping the dye on, two layers and gotten a nice, even, smooth, reddish brown colour on the leather. This time after the first layer all my leather was looking like in the attached image. Blotchy etc., as if I had been using too much dye (which can't be the case). The thing is, like I said, for past 4 years I've gotten my leather and dye from the same supplier and I've had 0 problems with my process, so I am a bit at loss here. I've ended up wasting a good 100 euros worth of leather now and a days work so far which annoys me.
Is this caused by grease or some other contaminant on the leather surface? Should I be cleaning my leather from now on before dyeing to avoid problems like this in the future? How to clean the leather? Any products to recommend or so?
The leather dye I've used with great success until now is ROC Narusværte, Danish leather dye.