Controlling HP5+ grain...agitation to blame?

[paul_klingaman]

Could constant agitation possibly be the cause of the increased grain I'm seeing with HP5+ in D76? I'm processing the stuff at the recommended 20 degrees in a Jobo processor. I've finally controlled the contrast to an acceptable level by reducing development time, but the grain is still slightly more apparent than I prefer. Before the purchase of the Jobo, I've been developing Tri-X in Xtol and D76...both with very nice tone and grain. A friend turned me onto this HP5+ stuff, so I thought I'd give it a try. I really like the tone, and the stuff is extremely cheap and versitile. However, is the grain normally this much a factor with this film, or is the constant agitation of the Jobo to blame? My understanding is that agitation influences contrast, not grain. Incidentally, I'm over-exposing the stuff 2/3 stops more than the recommended 400. Thanks in advance for your info.

[paul_klingaman]

Sorry...I should also mention I'm using a 1:1 dilution.

[john_hicks]

> Could constant agitation possibly be the cause of the increased grain I'm seeing with HP5+ in D76?

 

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Nope.

 

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> I'm processing the stuff at the recommended 20 degrees in a Jobo processor. I've finally controlled the contrast to an acceptable level by reducing development time

 

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I found that HP5+ requires a 25% reduction in development time (from intermittent agitation to rotary agitation) to match CI and curve shape. Could be you're overdeveloping but since you didn't have an intermittent-agitation starting point with the film that you know works the problem is that you don't have anything to compare it to. You might try reducing the development time by a further 10% or more.

 

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> Incidentally, I'm over-exposing the stuff 2/3 stops more than the recommended 400.

 

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Stop doing that unless you have a good reason to do so, such as insufficient shadow detail when the film's exposed at its rated speed.

[tim_brown5]

I'll amplify what John said: try to adjust exposure to a minimum

amount to get satisfactory shadow detail. Overexposing silver image

B&W film increases grain and reduces sharpness.

[marcel_perez_calisto]

"Overexposing silver image B&W film increases grain and reduces

sharpness."

Care to explain? Any scientific data to back this? How about pyro

developers that basically force you to overexpose? Thanks.

[steve_wiley]

Non-staining pyro developers are grainy. The stain masks the

grain.

[tim_brown5]

Overexposing any pictoral film reduces sharpness because of light

scattering in the emulsion, AKA irradiation. With minimal exposure

much of this scattered light remains below the threshold to produce

density in the final image. Grain increases because the higher the

density of silver grains the closer the grains are to each other and

the greater opportunity to clump together. Many, many photographers

over many, many years have observed this. Search the literature of

the manufaccturers etc. and you'll find documentation of these facts.

[marcel_perez_calisto]

Well Tim, I guess that all the many many many photographers over the

many many many years that have discovered that the manufacturers EI

is not always accurate (marketing???) and who constantly strive to

sqeeze the most out of the emulsion are all WRONG. And I guess they

should stop experimenting and sharing the results in forums like this

because they are not following the manufacturers recomendations which

are always RIGHT. Having said that, I am grateful that there is an

avenue like this where we can exchange info, even if not in

agreement, and hopefully improve as photographers...

[tim_brown5]

"Well Tim, I guess that all the many many many photographers over the

many many many years that have discovered that the manufacturers EI

is not always accurate (marketing???) and who constantly strive to

sqeeze the most out of the emulsion are all WRONG."<br><br>

Marcel, you are completely missing the message in my response.

Finding that your personal EI is lower than the ISO rating of a film

is NOT overexposing, it's finding the correct exposure for YOUR

equipment, YOUR developer, YOUR technique.<br><br>"And I guess they

should stop experimenting..."<br><br>Why don't YOU do this

experiment: expose a frame the way you normally do, then take the

same shot with exposure increased 2 stops (a flat, stationary subject

will help negate DOF and shutter speed effect). Make two similar

prints. Compare grain and sharpness.

[charlie_strack]

Further to the ISO rating & overexpose:

 

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ANSI/ISO use a film developer that isn't anything any of us would

use. They use an agitation technique that we don't use. They measure

speed in a way not many of us find practical.

 

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Manufacturer's don't up the film speed for marketing reasons--the

standards by virtue of the procedures used force a film speed that

isn't really practical. But it is "standard" that is, very repeatable

and the procdure is very conducive to lab testing.

 

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Note that Kodak and Ilford use EI indices in some of their new films.

They don't claim ANSI/ISO. In my opinion, a better option. Give us a

speed that really works--in general--rather than a speed that

corresponds to lab processing we'll never use.

[marcel_perez_calisto]

Tim, thanks for the tip. But that's the way I work anyway. If you

check 8 or 9 posts back you can read some of the results I got on

Acros film. But I have a question. My range was not 2 stops but 1 1/2

and shot three pairs (6 rolls total) at different EIs. After

processing at different times per pair I got 3 very good rolls (diff.

EI). I just went back and checked and re-printed some shots from the

three and still the lowest rated is the best. I use pyro and that

masks a lot of the grain but can't honestly say I notice a difference

in sharpness. Should the results be very obvious? I chequed thruogh a

8x loupe, and under the enlarger thruogh a peak grain focuser (6x7

negs). I made 8x10's and 20x24's (durst laborator + multigraph head

and Scneider HM lens). I believe what you say is totally true, my

question is when do you start loosing sharpness as a result of

overexposure. Thanks.

[tim_brown5]

Marcel, when you see the change in sharpness depends on how sharp the

image falling on the film is, when the film becomes the "weakest

link". Usually, a slightly longer than normal lens is the sharpest in

a manufacturer's line. If you're using an SLR you want to light with

strobe to minimize mirror and shutter shake, use a middle f-stop etc.

It might take 2 stops or more to see the difference in your case.

Shooting resolution targets and viewing the neg under a microscope the

drop in sharpnes with increased exposure is obvious. In real world

shooting it's easily swamped out.