Quote Originally Posted by pstake View Post
Has anyone ever heard of one? As in, one step above grade 5, which I've always known as the most contrast available.

I needed a #4 and #5, found three on ebay, #4, 5, and 6, see attached.

Was this for some specific paper?

I can't find any info about a No. 6 filter via Google.

Attachment 76229
filter numbers and ISOcontrast grades are not the same, unfortunately, but theoretically an ISOgrade 6 exists and can be reached with a tri-color -blue filter in combination with a very bright light source. Inever had a negative that needed such a high contrstbut tested tri-color filters fordual-filter printing.