using negative dry film

[johntech]

Having used the laser toner method of pcb image transfer to copper clad,and also positive resist,i want to use the negative dry film as it is very cheap,from youtube vids resolution is good.

This would be ideal as i could make single and double sided pcb's for pennies.
I use Tina7 pro Ind and find it very good for my needs,so far.
I  cannot find and means to invert the gerber images ,the standard track is positive imaged and no good for this abundant and very cheap dry film.

If i have to bite the bullet and buy new software that can output positive and negative gerber images then so be it,but if anyone knows how to sort this,and it seems some  people have this fixed,i can't for the life of me find anything ,i'd try printing and the photo copying,but scale may be altered,and that opens a can of worms to sort out.

Plus my version of Tina is on a cd-rom not a subscribe per year scam,pcb houses for what i make charge way too much,as i say ,i can make for pennies even with toner,it's just a pain sorting out missing toner,and a single fieche can last for ages ,positive dry film is quite expensive for some reason,spray resist is inconsistant.

Any help here would i believe help more than myself.
cheers.