marks on negative

Hi,
very often I get marks of diferent sizes on my negatives. I use perceptol or microphen most of the time in stock solution witch I reuse- I think this might be the problem.
I think these are not water marks becouse rewashing of negatives does not help.
Linked photo is crop of one of my enlargements. The mark is on the top and in the middle of the frame.



Thanks

here is the link
http://yfrog.com/5z14106012j

I suspect that you need to use PhotoFlo after washing the film.

Steve

I use photoflo but i dont think that is water mark

You have hard water?

If you hold the negative at the right angle to the light, can you see a texture of it? It is plus density so either it is caused by something making the developer more active right there or it is caused by some substance physically on the negative. Usually marks on film are minus density making dark marks. Plus density is usually either edge surge or bends in the film base or Photo flo residue.
Dennis