Saturday, February 19, 2022

Erasers Leave an Oily Residue

Many erasers leave an oily residue, which can result in paint chipping from its backing surface.

Note how the gouache paint on this Coby Whitmore is chipping off the girl's hair and the background.

This YouTube video shows how erasers are made.


This is one of the topics I explore in this one-hour workshop on YouTube. It's a sample of the full 93 minute tutorial video available from Gumroad  and Sellfy

6 comments:

Bob said...

James,
Once again you've opened our eyes to something certainly I wouldn't have thought of. I imagine that this issue happens because oil and water doesn't mix. In turn this suggests that the effect would be different for oil paints. And of course, my iPad's eraser leaves no residue at all (sorry I'm incorrigible).

Joel Fletcher said...

Interesting topic. I have wondered about eraser residue, and possible issues with paint. It makes sense that kneaded erasers would leave a residue, as they must have extra plasticizers in order to make them soft. However, the "crumbly" regular erasers can wear paper down, and potentially leave particles embedded in canvas. Hard to say which is better.

That being said, I have used kneaded erasers on my acrylic on canvas paintings and have never seen any sign of paint failure. And I have used these erasers since the seventies. Maybe this is more of an issue with paper substrates, and certain paints? I wonder if eraser residue effect on paint has been studied at all?

Paul Sullivan said...

This is very interesting. I would think that a kneaded eraser would leave more oil residue on illustration board than a pink pearl. What are your thoughts on this.

widdly said...

If I have overworked an underdrawing and worn down the paper too much with a crumbly eraser, is there something I can paint on worn surface so I can apply watercolor smoothly?

Mario said...

I have always been suspicious about kneaded erasers, and I tend to avoid them in watercolor paintings (they are sticky, and they collect the grease from fingers). I'm not sure if good quality "solid" erasers have oil in them, the ones shown in the video seem school products.
Anyway, I'm a bit puzzled about the Coby Whitmore painting. It's reasonable to think that an erased has been used in the woman's hair (but strangely not in the face or in the soldier's hand), but what about the sky in the upper left corner? What did the artist erase there? Obviously we don't know exactly, he may have erased an airplane o some birds, but I think the paint may have fallen for other reasons, for example the support has been bent or scratched, or the paint had some problems in the formulation or the application. Also, are all gouache paintings from that era cracking and chipping off? I guess all the illustrators used erasers.

Joel Fletcher said...

I researched this matter a bit. Kneaded erasers are made from unvulcanized rubber, and not likely to leave residue on surfaces. However, kneaded erasers are somewhat sticky and will absorb skin oils, hand lotion, etc. from use. Especially from "kneading"! Therefore older kneaded erasers could transfer those hand oils to the erased surface. So I would suggest throwing out older well-used ones, and replace with new. Kneaded erasers are inexpensive.