Incorporating filter factor in push developing

[tron_]

I recently shot a roll of Ilford HP5+ pushed to 800. I will be developing the film in a 1+50 dilution of Rodinal for 16 minutes (as per the massive dev chart). When I took the photos, I had a Hoya K2 filter on the lens which has a filter factor of 1 iirc. By how much should I adjust my development times in order to compensate for the filter?

Also lets try not to turn this into a Rodinal debate please

 

[Karl A]

With the filter you lose one stop, so you in effect shot it at 1600, if you didn't compensate for the filter in your exposure. So you should develop it as you would for 1600. Hope that helps?

 

[Gerald C Koch]

As mention on another recent thread, Rodinal is NOT the best developer for pushing. Try a developen that contains Phenidone or one of its derivatives like Acufine, Microphen, Xtol, Diafine.

 

[Xmas]

One hour stand at 20C and 1:100 might be better?

 

[Terry Christian]

Stand develop only if you can afford to lose some contrast. Stand is nice, but it isn't a cure-all!

Personally I'd develop normally and let the latitude of the film handle it... or maybe add a minute or so to your development time if you feel you must.

 

[tron_]

That makes sense, honestly I never really put it together that a filter factor of 1 meant 1 stop under exposure.

I've pushed hp5+ to 1600 in rodinal before so I'll give it the same recipe. I can't believe that filter cuts out one full stop of light.

 

[tron_]

Terry, the recipe for a one stop push calls for a 1+50 dilution for 16 minutes. The two stop push (which I've done before) calls for a 1+50 dilution for 24 minutes. So that's an 8 minute difference according to massive dev. Eek.

Also you're right about latitude but I'm not sure how much hp5+ has

 

[Mark_S]

Stand develop only if you can afford to lose some contrast. Stand is nice, but it isn't a cure-all!

Personally I'd develop normally and let the latitude of the film handle it... or maybe add a minute or so to your development time if you feel you must.

If he has shot HP5+ at an EI of 1600, he probably has plenty of contrast to lose

 

[tron_]

Just for reference, here are a few shots from when I pushed HP5+ two stops in a 1+50 concentration of Rodinal (24 min dev time). I know the shots are not for everyone but I really enjoy the inky blacks you get from pushing.

 

[kintatsu]

Putting aside all other parts to this question, a K2 has a factor of 2 or 1 stop to offset the decrease in lights at the blue end of the scale. If your light was predominantly blue, below say, 500nm, then the factor needs to be applied as mentioned. Between 500 and 700nm, the factor would be less. Beginning at 500nm the percent passed is 63.5 up to 91.4 at 700nm, so the factor is based on the lower end of the spectrum, your blues.

I've often applied 0 to 1/3 stop if the use of the filter was only to increase contrast in the sky or clouds. Therefore, if your scene would be improved by not applying the factor, then you needn't change development. At least to my way of thinking, and based on your samples, you should be fine giving your usual development for similar exposures and similar shots.

BTW, those are some nice photos!

 

[tron_]

I'm always amazed at the amount of knowledge on this forum, I can't tell you guys how much I appreciate the help and how happy I am to be a part of this forum.

Kintatsu, when I shot the photos, it was late afternoon/early evening ("golden hour"). The sky was clear and the scenes were fairly contrasty as far as I can recall. I threw on the yellow filter to get a little more contrast in the sky so I should develop roughly at the same times as a 1 stop push?

Edit: Oh and thank you very much, Kintatsu!

 

[DREW WILEY]

For most practical purposed, filter factors have nothing to do with pushing or pulling. They relate to how much more exposure you will need
to offset the density of the filter itself, right at the time you make the exposure. And this will differ with the kind of lighting, though generally
you just need to differentiate between gross differences, like that between outdoor natural light and indoor tungsten lighting (heaven help us
with all these new abominable CFL & LED sources!)

 

[kintatsu]

I would suggest developing it as you had originally planned. Golden hour has slightly more yellow light, so other than the sky, there was probably not enough to justify a large increase in exposure. It should leave you with something that won't be a disappointment. Of course, that's how I would do it, someone else may have a better idea, and that'll help us all out!

I'm with you about being amazed. Some great folks are here, and lots of information. APUG is always my first stop of the day!

All the best and I hope your film comes out great!

 

[kintatsu]

(heaven help us
with all these new abominable CFL & LED sources!)

Especially when your shooting the nasty D-word or color!

 

[cliveh]

You should compensate for the filter during exposure, not development.

 

[kintatsu]

For most practical purposed, filter factors have nothing to do with pushing or pulling. They relate to how much more exposure you will need
to offset the density of the filter itself, right at the time you make the exposure...

You should compensate for the filter during exposure, not development.

I forgot to mention that. I assumed he hadn't calculated that into his exposure. I know what happens when I assume...

But given his situation, it should come out nice with his planned development. At least to my way of thinking. I hope I'm not wrong there.

 

[tron_]

I was planning on compensating for the filter factor when I was out shooting but realized I didn't understand 100% how to compensate for the filter on my camera. I might be eager but that doesn't mean my neurons always fire correctly

I just finished developing the film. Massivedev called for 1+50 for 16:00 for a push to 800. I gave it 16:30 just to bump the development time up to compensate for the filter somewhat-ish (see neuron comment above).

Well the film is drying and I must say the negatives look pretty good. Of course when they are all dry and finished I will be sure to post them here (hopefully later tonight).

Again thanks for everyone who posted, can't wait to see how they turn out!

 

[pentaxuser]

Massivedev called for 1+50 for 16:00 for a push to 800. I gave it 16:30 just to bump the development time up to compensate for the filter somewhat-ish (see neuron comment above).

Well the film is drying and I must say the negatives look pretty good.

As long as the negs look OK this is fine but in terms of extra development 30 secs represent only 3% which I'd have thought makes no difference at all. 30 secs might be significant when the dev time is say 6 mins but at 16 mins it probably makes no difference at all. Once you get to 16 mins then even 2 mins extra is only 12.5 %

Just a thought

pentaxuser

 

[Karl A]

I can't believe that filter cuts out one full stop of light.

Yup, the filter factor is actually 2, that means 2 times the amount of light required, so it requires double the time or one stop more open on the lens. A lot of red filters are 8x factors, which is 3 stops so the yellow is not too bad actually

Those factors are averages under daylight conditions, so there can be variation, as others mentioned. Also check the tech sheet for your film, it may suggest compensation for different filters specific to your film.

Glad it worked out fine in any case

 

[tron_]

For anyone interested in the results here are a few frames from the roll. Overall I'm pretty happy with how they turned out, I figured I would update the post in case anyone else in the future has the same question as me!

Thanks again APUG, I think I got lucky with the developing this time!

Camera: Mamiya RZ67
Lens: Mamiya Sekor 110mm f/2.8
Filter: 77mm Hoya K2 (yellow)
Film: Ilford HP5+ shot at 800
Developer: Rodinal (substitute, it's really Adox Adonal)
Development time: 16 min 30 seconds
Metering: I DID NOT compensate for the filter in my metering

 

[kintatsu]

For anyone interested in the results here are a few frames from the roll. Overall I'm pretty happy with how they turned out, I figured I would update the post in case anyone else in the future has the same question as me!

Thanks again APUG, I think I got lucky with the developing this time!

Those are some nice pics!