what is the difference between positive and negative layer?

[liletian]

Hi Guys
When I submitted my design, I have to specify is the layer is positive or negative. I know I have to use positive layer. But what is the difference between positive and negative layers?
Thanks,
B

 

[enjunear]

If you have a positive layer, you can create a positive mask. That means that the transparent film that the artwork gets printed on (for the photolithography tool), is opaque (black ink) where the copper/conductors/polygons will be. If you had a negative layer, then the mask would turn out being all black; except where the traces would be, it would be clear.

Positive and negative layers are identical in terms to the photography terms. In black & white photos, the negatives (developed film) were inverted from the colors on the final photograph.

 

[kevin54]

Positive = Anything drawn on that layer represents material (copper, solder paste, ink)
Negative = Anything drawn on that layer represents absence of material (opening in solder mask)

 

[liletian]

Positive = Anything drawn on that layer represents material (copper, solder paste, ink)
Negative = Anything drawn on that layer represents absence of material (opening in solder mask)

that is my guess
thanks a lot