Reciprocity for Delta 100

[Joanna Carter]

Having been an Acros addict for a while now, I need to start using Ilford's Delta 100 to extend the life of my Quickload stock :-)

Now, those of us who use Acros will know of its amazing reciprocity characteristics but, looking at the curve that Ilford supply for Delta 100, it would appear that all Ilford have done is to copy the same curve for all their emulsions. I'm sorry but, I refuse to believe that a 50 ISO film has exactly the same reciprocity as a 3200 ISO film.

Does anyone have any real world experience of long exposures and reciprocity with Delta 100?

[percepts]

As with all HD curves, reciprocity curve is subject to processing conditions. i.e. which developer, time and temp etc. Therefore you can not rely on any published curve.
However, assume that the Ilford curve is for reciprocity of the highlight values.

What I mean by that is that a night time image or indoor image may have areas in bright light and some in areas of very deep shadow thereby creating a scene with a very large subject range. Base you exposure on the highlight value and there may be no reciprocity. Base it on the shadow and it will tell you there is reciprocity. Which is correct? Using the highlight value will work better than using the shadow. For black and white use development for a 10 stop range. In most circumstances that will give you very good results using Ilfords chart. Use the shadows for setting exposure and the chart will cause you massive over exposure to highlights.
I have found the Ilford chart good for HP5 using exposure as I have suggested. I see no reason why it won't work just as well for Delta.

[Keith Tapscott.]

Does anyone have any real world experience of long exposures and reciprocity with Delta 100?Not personally, but you might find this (http://www.willwilson.com/articles/0403Bond_Reciprocity2.pdf) useful.

[Marko]

Having been an Acros addict for a while now, I need to start using Ilford's Delta 100 to extend the life of my Quickload stock :-)

Now, those of us who use Acros will know of its amazing reciprocity characteristics but, looking at the curve that Ilford supply for Delta 100, it would appear that all Ilford have done is to copy the same curve for all their emulsions. I'm sorry but, I refuse to believe that a 50 ISO film has exactly the same reciprocity as a 3200 ISO film.

Does anyone have any real world experience of long exposures and reciprocity with Delta 100?

Since you are now manually loading Delta 100 sheets, why not manually load Acros and stay with the emulsion you like and are used to?

They are still making Acros, they just stopped producing the Quickload....

[Joanna Carter]

Since you are now manually loading Delta 100 sheets, why not manually load Acros and stay with the emulsion you like and are used to?
Because, as yet, nobody in the UK is selling the sheet film :confused:

[Marko]

Because, as yet, nobody in the UK is selling the sheet film :confused:

If you can purchase across The Pond from eBay, why not from Badger?

[Joanna Carter]

If you can purchase across The Pond from eBay, why not from Badger?
The way that Fuji UK behave, that may well be the only way to get hold of it :mad:

[DJGainer]

freestyle has it too, for slightly less than badger. still waiting on b&h's price point before I make a decision whether or not to try the loose sheets.

[Michael Rosenberg]

Joanna,

I have found the reciprocity behavior of Delta 100 (exposed at ASA 100), developed in Xtol 1+2, to be excellent. I do not do any correction up to 2 min, and add 5 sec every 15 sec increment up to 4 min. Fine grain in Xtol, but not as fine as TMY2. I process in a Jobo 3010 tank at 22C for N=9:00 min.

[Lenny Eiger]

Not personally, but you might find this (http://www.willwilson.com/articles/0403Bond_Reciprocity2.pdf) useful.

Not useful. Incorrect.

Joanna, try this: we just tested this earlier this year. They are an approximation based on shooting outside and reading with densitometer, and as always, where one points the meter controls a lot of things... It's been working well over a series of trips...

Meter Shoot at
1 1
4 5
8 11
15 26
30 50
1 min 2 min
2 min 5:15 min

Give it a whirl - it works for me....

Lenny

[Sal Santamaura]

Not useful. Incorrect...Are you saying Howard published incorrect data or that your conditions and methods provide different results? ;)

[Lenny Eiger]

Are you saying Howard published incorrect data or that your conditions and methods provide different results? ;)

I found the data to be incorrect (incorrect for me). Just like I find most manufacturers recommendations to be incorrect. I shoot outside, in a specific area of the country, and made a few tests. They appear to work for my shooting style, the type of light around here (West Coast, USA, etc.)

He was also doing this in 2003. Is the film we use today the same film? His development will be different. There are so many variables.... The type of print one wants, what a Zone 3 really is, etc. I will tune my numbers over the next year or so and move them a little here and there... Mine are meant to be a general recommendation to start with, not an end.

Are you asking me if I am trying to make a public slur at Mr. Bond? Why would I want to do that?

[Philippe Grunchec]

Joanna, you can find it easily in France!

[venchka]

Thanks Lenny. One question: What E.I. did you set in the meter?

[Joanna Carter]

Joanna, try this: we just tested this earlier this year. They are an approximation based on shooting outside and reading with densitometer, and as always, where one points the meter controls a lot of things... It's been working well over a series of trips...

Meter Shoot at
1 1
4 5
8 11
15 26
30 50
1 min 2 min
2 min 5:15 min

Give it a whirl - it works for me....
Thanks Lenny, that's certainly a lot better than the Ilford chart which, when extrapolated to a function, would give:

1 sec 1 sec
4 sec 9 sec
8 sec 25 sec
15 sec 1 min 2 sec
30 sec 2 min 46 sec
1 min 7 min 26 sec
2 min 20 min

Howard Bond gives:

1 sec 1 sec
4 sec 4.5 sec
8 sec 9 sec
15 sec 19 sec
30 sec 41 sec
1 min 1 min 33 sec
2 min 3 min 50 sec

... which I am hopeful would work but are a bit shorter than yours.

Hmmm, I gues there's nothing for it than to burn a roll of 120 and see what I get.

[Keith Tapscott.]

Thanks Lenny, that's certainly a lot better than the Ilford chart which, when extrapolated to a function, would give:

1 sec 1 sec
4 sec 9 sec
8 sec 25 sec
15 sec 1 min 2 sec
30 sec 2 min 46 sec
1 min 7 min 26 sec
2 min 20 min

Howard Bond gives:

1 sec 1 sec
4 sec 4.5 sec
8 sec 9 sec
15 sec 19 sec
30 sec 41 sec
1 min 1 min 33 sec
2 min 3 min 50 sec

... which I am hopeful would work but are a bit shorter than yours.

Hmmm, I gues there's nothing for it than to burn a roll of 120 and see what I get.Shoot 3 rolls Joanna, one as Ilford suggest, the next according to Howard Bond and the third as Lenny recommends, then compare the results.
That should keep you busy for a little while. :D

[Lenny Eiger]

Thanks Lenny. One question: What E.I. did you set in the meter?

We set it to 100. Both 100 and 80 worked very well. It was the only one that worked for us right at its stated ISO.

Lenny

[Sal Santamaura]

...Are you asking me if I am trying to make a public slur at Mr. Bond?...Certainly not; that's why I included a ;).

Use of the term "incorrect" in this context can be problematic. There are many variables involved. Howard Bond tends to be fastidious about reporting the conditions/procedures of his tests, so I usually accept his results as correct in those circumstances. Use of different procedures under other conditions typically results in different data. That's why, in my view, both your and Howard's reciprocity data are correct. The only absolutely reliable corrections are those each individual photographer develops for themselves.

[Lenny Eiger]

Thanks Lenny. Hmmm, I gues there's nothing for it than to burn a roll of 120 and see what I get.

As to the thanks - well, anything I can do to help to get you working on an 8x10 sleeve holder ;-)

As to the roll film. I have often found it difficult to compare roll film to sheet film. I use a Jobo and I have to set it to a different speed to process (more agitation). It also appears to be different film on occasion. Once you do a few rolls, I would say confirm what you find with some sheets...

Lenny

[Lenny Eiger]

Certainly not; that's why I included a ;).

Sorry I missed that.


Use of the term "incorrect" in this context can be problematic.

You're right of course. I am busy at the moment and not choosing my words carefully enough. I was also frustrated to find out that his well illustrated article that looked so authoritative - wasn't going to work for me.

I also found other references that suggested all sorts of magic things about almost no reciprocity needed for some film, and it's just not true.

My numbers aren't dead-on either. The shorter numbers are going to be closer, as the "where you point your meter" variable on longer exposures can throw you a loop. I find I often qualify my longer exposures by what I think is reasonable, which is quite subjective. Yet, I have made the last 50 sheets with great exposure and development, not a single sour apple in the bunch. That's a happy thought... or in this case a happy experience.

Lenny

[seabird]

Lenny, thank you for posting your Delta data. I dont mean to hi-jack the thread, but did you also test FP4+? If so, can you share your results? Thanks.

[Lenny Eiger]

Lenny, thank you for posting your Delta data. I dont mean to hi-jack the thread, but did you also test FP4+? If so, can you share your results? Thanks.

I didn't specifically re-test this in the last round. I have always used the old standby.

time add
1 sec 1 stop
10 secs 2 stops
100 sec 3 stops

Or, to remember, if the number has 1 digit, then its 1 stop, 2 digits, 2 stops, etc. I did interpolate for 5 secs (1.5 stops to add). I don't know if its perfectly accurate, but it gets you in the ballpark with most traditional film....

Efke is the most difficult. The shorter amounts work fine in that scenario, but as the time gets longer, even more time is needed.

I hope this helps,

Lenny

[tgtaylor]

Having been an Acros addict for a while now, I need to start using Ilford's Delta 100 to extend the life of my Quickload stock :-)

Now, those of us who use Acros will know of its amazing reciprocity characteristics but, looking at the curve that Ilford supply for Delta 100, it would appear that all Ilford have done is to copy the same curve for all their emulsions. I'm sorry but, I refuse to believe that a 50 ISO film has exactly the same reciprocity as a 3200 ISO film.

Does anyone have any real world experience of long exposures and reciprocity with Delta 100?

Hi Joanna,

Like you, I have been an Acros addict for several years now. Starting with QL's, I switched to sheets a couple of years back to save $ + weight and bulk on backpacking trips. Frankly, I've come to enjoy the "holder experience." Somehow it is more "photographic experience" to me when using holders and there is no envelope hanging out in the wind to pick up vibrations.

To answer your questions, last winter I shot a box (25 sheets) of Delta 100 in Yosemite with the last 3 sheets taken indoors in Mariposa. Two sheets were exposed in an old upstairs courtroom in the Mariposa County Courthouse. Working with a 90mm f4.5 Grandagon my meter indicated a normal exposure of 15 seconds which translate to 55 seconds on the Ilford curve. Both negatives came out superb with normal development @ 68F. The third sheet was shot inside St Joseph's Church. It also came out superb using the Ilford’s curve.

[willwilson]

I use Howard Bond's numbers mostly, but there are so many different variables when shooting in low light that experience will really be your best guide. Development has a lot to do with low light exposure as well. I often will move a shot into reciprocity with a neutral density filter for the increase in contrast.

Sometimes the meter says 30s and the chart says to give it 41s but you know that it really needs 1m just because of the way the light is hitting the scene. I have yet to make a negative that is too dense to work with but I've got a few that I wish had some more density.

I usually count anything under 20s and use a watch for longer times, so with the shorter exposures I lean towards a little extra time with a slow verbal count, a little quicker if I am going to do N+/N++ and a little slower for N-/N--. I recalculate exposure totally if I am going to do some type of compensating development. I use the first 5 or 6 spots on my chart all the time and they work great. I typically rate Delta 100 at 75 or so. I use Xtol and rotary development.

I think if you are doing anything longer than a few minutes then you are mostly making an educated guess. I know my meter doesn't work well in that kind of light (Soligor Spot II).

Here's the chart I use (It's taped to my meter along with some other junk):
2s - 3s (I usually shot these at a long verbal counted 2s)
4s - 5s (this says 8s on the chart taped to my meter instead of 5s. I keep meaning to change it but I haven't. I have shot lots of things that metered at 4s and should of gotten 5s but they were shot with an 8s exposure by mistake and they are always fine or at least I haven't been able to tell!)
8s - 9s
15s - 19s
30s - 41s
1m - 1m 33s
2m - 3m 50s
2m 40s - 5m 13s
3m 20s - 7m
4m - 9m 20s
8m - 20m

[Hans Berkhout]

A reciprocity failure situation becomes more complicated if the illumination is not constant during the exposure time. How to deal with sun rising or setting?- deviation from the correction tables may be necessary. I must admit that I haven't tested for this!

[spiky247]

another complication to consider is how contrasty the scene is. if you are shooting a city scape at night with a lot of contrast, the exposure compensation may vary greatly depending on where you want to put your mid tone.