Stippled/waves effect on yellow colour.

[Anne_83]

[FONT=&quot]I'm sublimating small 8x6 inch aluminium sheets on my Stahls Maxx 38x38cm heat press. Everything looks great, except I've noticed that the yellow colours appear to have a stippled/waves type texture to them. Every other colour is fine.[/FONT]
[FONT=&quot]Settings are as follows: 180c for 70 secs, medium pressure.[/FONT]
[FONT=&quot]I also sublimate mousepads and mugs using the same inks and paper but have only ever encountered this problem when sublimating (white coated) aluminium sheets.[/FONT]
[FONT=&quot]Does anyone know what might be causing this, please?[/FONT]

[webtrekker]

What pressure are you using? I get best results on aluminium using very light pressure, so light in fact that it's virtually just the weight of the top platen providing the pressure.

I also press between sheets of copy paper or kitchen roll to reduce the effects of moisture, which usually appears as a 'marbled' effect.

[Anne_83]

Thank you for your reply. I'm also using a very light pressure and copy paper (two sheets top and bottom). Since my previous post I've taken a closer look at my actual print outs (from Sawgrass SG400) and have discovered that this effect is actually many small dark dots. It's definitely not a dust issue as I have printed the same image a few times at the dots appear in the exact same place. I've attached a close-up of a scan of the printed page. The image shows what should be a white square and a yellow square. In Photoshop, zooming right up close to the original image shows pure white and yellow with zero dots.

After a little bit of googling I'm thinking this is some kind of "dither" setting, but I don't really understand how that works! I know that in my printer settings dither is set to "automatic" at the moment.

Any advice would be appreciated. I suspect this problem has always been going on when I print mugs, but because the images are smaller it is almost unnoticeable on them, but on larger metal prints it is very clear to see.


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[webtrekker]

What model of printer are you using? Dithering can be a problem on printers with only 4 colours (CMYK). Is the resolution of your original image adequate, ie 300dpi or more without scaling?

[Anne_83]

Printer is a 4-ink Sawgrass SG400. My printer resolution is set to 600 dpi. My original images are all done at 300 dpi. I'm also printing via Photoshop.