Marco, what does this "watercolour tape" look like? I went to buy some today in an art store, and they sold me what looks like old-fashioned butchers tape - that is, kraft paper with glue on one side.
Hi Johnny,
Unfortunately, I'm not familiar with the terms "butchers tape" or "kraft paper" (I'm dutch). However, even on English Art / Watercolor forums, I have not yet seen it referenced like that... so it might be the wrong tape.
The tape should be bright white and have a one sided glue layer, the side of which is a bit glossy. Please note that the glue layer is non-adhesive when you buy it! It must come into contact with water to achieve it's adhesive properties. If your tape is already sticky / adhesive, it's definitely the wrong kind of tape.
Since the tape is for artist purposes, both the tape and glue are also acid free and buffered, just like we want in photography due to archivability requirements.
A well, Google now showed me the way to some "brown" colored "kraft paper"..., and NO, that's not how my tape looks
, this tape sure doesn't look like an acid free tape type, again, it should be bright white...
I think it's time to visit another art shop
. A good shop *should* be able to help you out!