# Laser leaves ash film on top

**URL:** https://forum.onefinitycnc.com/t/laser-leaves-ash-film-on-top/19310
**Category:** J Tech Laser
**Created:** [March 9, 2023, 3:06pm UTC](https://forum.onefinitycnc.com/t/laser-leaves-ash-film-on-top/19310 "2023-03-09T15:06:03Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![GregoryG](https://avatars.discourse-cdn.com/v4/letter/g/97f17d/32.png) [@GregoryG](https://forum.onefinitycnc.com/u/GregoryG)
#### Post date: [March 9, 2023, 3:06pm UTC](https://forum.onefinitycnc.com/t/laser-leaves-ash-film-on-top/19310/1 "2023-03-09T15:06:04Z")

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Hi I have the j-tech 7 watt laser that I have been trying to perfect photo lasering on different materials ceramic wood canvas Etc lately on canvas which is painted white and then black on top has been leaving a film sort of all I can figure is it’s Ash or some of the burn off I have to take the canvas and wash it off and if I’m not careful at all doesn’t wash off it will smudge  
After I wash and before pictures this did not happen till recently I have tried adding air assist problem continues

 ![20230309_065908](https://us1.discourse-cdn.com/flex022/uploads/onefinitycnc/original/3X/c/0/c0852c99cdaafd95d1c66339d2288ff0d34b8826.jpeg)  
 ![20230308_212831](https://us1.discourse-cdn.com/flex022/uploads/onefinitycnc/original/3X/e/c/ec054e446238d3ccfc7dc358ea9d84268461a71e.jpeg)