Friday, May 6, 2022

Lightfast Testing: Tape Fail!


4/25/22 Tape fail!

[Some of you may have seen this post briefly a few days ago. I somehow managed to schedule it for posting in the past on April 6 instead of May 6 -- which means my reference to removing the tape on April 25 would have made no sense. So I deleted it and rescheduled it for today as planned. Time travel is possible -- at least on my blog!]

At the end of December, I had set up a page of swatches to test the lightfastness of watercolor pencil pigments to compare their dry and activated states. The test sheet had been exposed to a southern-facing window for more than five months, and I had been looking forward to revealing the results.

On April 25, I carefully peeled off the tape – and it was a huge fail! The Pro Artist Tape I had used took the pigment off and even ripped the paper in a couple of spots. So the differences you see are not changes from light exposure – they are simply where the pencil pigment adhered to the tape. I do think that if the pigments had faded significantly, that would be apparent even in this condition, but I don’t consider this a legitimate test result.

The only times I’ve used this tape were for short-term uses, so I didn’t know the adhesive would do this. Next time, I guess I have to test the tape for long-term use before I make the lightfast test. What a bummer! 

12/23/21 Test sheet with tape


  1. In my lightfastness testing I found that all masking style tapes left gummy or crusty residues on my windows and paper. I now slice a section of the pencil/pen sample I'm testing out of the sketchbook and adhere that to the window with scotch tape and then tape it back into the sketchbook after the test. I have a window with little blobs of glue all over it from masking tape- I've used a razor to scrape it off with some success.

    1. Thanks for your suggestion! I'll do that next time I try this. (I saw your comment on the post I deleted, too.) By the way, I have tried many times to comment on your blog, but it never lets me. :-( (I have that problem here sometimes on my own blog, too!) But I do enjoy reading your blog.

    2. It's the Disquis widget. I don't know why it does that to some people sometimes. I'd say try again but I know the frustration.

  2. Too bad the tape spoiled the test. I guess that was rather unexpected.


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