Scaling seems to be a problem with many (or all) laser printers.
But I have not had too much of an issue with it with my old Lexmark T522.
For toner-transfer, I print from KiCAD (PCBnew) directly with "Accurate Scale 1" chosen and both scale adjustments at 1.000000 (default)
I did measure recently a 100mm x 100mm square which came out to something like 99.5mm x 99.8mm which seems good enough for what I do (Through hole and large SMDs)
That was on plain paper. I don't know if it changes on TTS as I haven't used that yet.
So far, I've only used thin magazine paper taped onto plain paper.
For UV process I use negative resist, so I have to export from KiCAD as a negative plot postscript file (again, no scale changes) load in GIMP, and print out on a transparency (Then, I use the whiteboard marker trick to darken it)
I did find out however that I have to make sure to ignore borders and increase the page size to correct size in the print settings or it shrinks everything badly. Again, size is not exactly spot on, but it's good enough for me.
Of course, if all your printing is direct from KiCAD without other formats\software involved, then I guess it is the printer itself.
Are you changing the software settings for the different paper? Maybe try changing if you are not, or not changing them if you are... I don't know otherwise.
--- In Homebrew_PCBs@yahoogroups.com, "godzilera" <yah.5.peteben@...> wrote:
>
> Although I have been making successful single-sided PCBs for a while now, I just recently decided to try making a double sided board with SMD (.5mm TQFP) parts. So, I went out and bought a new inexpensive Samsung ML-2165 printer. The problem I am having is getting the scaling right. It's inconsistent and varies from print to print. Plain paper works pretty good, but the Pulsar paper comes out too short. I tried adjusting the scaling in the Kicad print dialog, but it seems to come out either too wide or too short. Very frustrating, and I have wasted four sheets of TTS paper so far.
> I have a couple of boxes of HP glossy photo paper, so I may try that.
>
> Any advice?
>
> Thanks,
>
> Pete
>