Ilford #5 is different from Kodak #5+, which is different from Wratten #47b. The latter is much denser than the former, but I don¹t know what the difference might be and it will depend on the emulsion used. Nevertheless, don¹t expect a huge difference. That said, Wratten #58 is a huuuge difference over the soft filters from Kodak and Ilford. It is soft beyond practicality. Regards Ralph W. Lambrecht http://www.darkroomagic.com On 2005-09-19 10:02, "Peter Badcock" <peter.badcock@xxxxxxxxx> wrote: > OK. So I just did a bit of reading about how contrast is controlled on VC > papers, and it is set by the ratio of blue:green light. Magenta filter is > red+blue (no green). Since the paper is insensitive to red, the blue light > component in magenta is all that is seen by the paper. The only way I could > see that a #47b blue filter would offer any increase in contrast is if it's > ration of blue:green is > than the ratio of blue:green in the magenta filter. > These wratten curves ( http://www.geocities.com/thombell/curves.html > <http://www.geocities.com/thombell/curves.html> ) don't give an answer since > neither #33 nor #47b show any green component. I'd rather not buy a blue > filter if the effect will be marginal or un-noticeable. Maybe Ilford's #5 is > not the same as wratten#33. > > regards > Peter > > On 9/19/05, DarkroomMagic <info@xxxxxxxxxxxxxxxx> wrote: >> Peter >> >> The blue filter is Wratten #47b. You might have a #25 Red, which is part of >> the tricolor series. The third one is #58 Green. The green filter is the >> softest and the blue filter is the hardest you can get from your paper. They >> are not readily available except for the red filter, but they can be ordered >> from all major filter manufacturers. Mine are from Tiffen. >