Wratten colour correction filters for b&w

[jukka1]

<p>Hello!<br />I got large set of wratten gelatin filters for colour correction.<br />Can these be used for bw and much do they affect?<br />For example 85b is orange but only needs 2/3stop exposure correction whereas orange glass filter requires about 2 1/2 stops. Is this gel filter as affective in bw as glass filter?<br />how about yellowish gelatin filters?<br />These are 75mm * 75 mm I would like to use them with my Hasselblad compendium with filter holder.<br />Sincerely, Jukka</p>

[dave_s]

<p>Try it and see. I've never tried to use color conversion filters (like the 85B) with B&W film, but you can predict it would have a much weaker effect than a contrast filter like an orange 21.</p>

<p>If you want the details, look for a copy of the old Kodak publication B-3, <em>Kodak Filters for Scientific and Technical Uses.</em> It has the absorbance spectra of different Wratten filters. The 85B has a sloping absorbance curve, so it takes out 98% of the violet (400nm) and maybe 60% of the blue-green (500nm). A 21 completely cuts off everything shorter than 540nm.</p>

[leicaglow]

<p>Jukka, It has been since the early 80's since I've really dealt with Wratten numbers (it as more common back then).<br>

To answer your questions, if a filter is orange, yellow, red, whatever, then it transmits that color to the B&W film, regardless of what it was intended to do. If there is a difference in exposure compensation, it is only due to the amount of light going through the filter, so a filter needing less correction would indicate it is not as intense (dense) as the comparative filter. If you are talking about an O56 Orange filter, I would double check your number. It should be somewhere around 1 stop compensation.</p>

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[q.g._de_bakker]

<p>A 85B is a colour temperature correction filter, not nearly as effective as a contrast filter as a 16 or 21 orange filter. And indeed with only a 2/3 stop correction required.<br /><br />A yellowish gel may be a yellow contrast filter, or a colour correction filter (what does it say on it or on the package?). In the latter case, it will be weak too compared to a 8 yellow filter.</p>

<p>Mind that some lenses need filters larger than these 75 mm filters. What lenses are you going be using them on, and in what shade?</p>

<p>A 56 filter, by the way, is a green filter. ;-)</p>

[leicaglow]

<p>Q.G., Green is a 58 ;-)</p>

 

[dave_s]

<p> . . . and light green is a 56. :>)</p>

[q.g._de_bakker]

<p>Badaboom!<br>

;-)</p>

[q.g._de_bakker]

<p>I still love this editor and how it inserts posts into the database...<br>

[Duplicate post removed]</p>

[john_a5]

<p>Even the strongest of the CC filters is not going to much with b/w film, but may have some effect and in certain cases, maybe enough. The biggest problem is just having to carry then all around and trying to figure out which is going to help--unless you have a lot of instant film to burn (do they even make b/w instant film anymore??) But generally, the normal contrast filters range in effect anyway, like the yellow versus the orange versus the reds--so carrying around small CC filters doesn't really make a lot of sense. I have a ton of them and they just sit in a box stored away, haven't needed them since I stopped shooting interior architecture on transparency film!</p>

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