OverExposing Color Negative, Decreased Grain

[howard_slavitt2]

I've read in various forums that when shooting color negative, in

particular, Portra 160 NC, if you overexpose (i.e. shoot it at 100

ASA vs. 160 ASA), then you'll get less grain. For those who have

used this technique, I assume you just develop normally rather than

push processing it?

[art_haykin]

While it is true that grain is more apparent in thinner densities, overexposing by about 1/2 stop will not producedramatic results in the grain reduction dept. And if you DIDexpose ISO 160 at 100, you would NOT necessarily have it "pushed," as that would increase the density and contrast. Onenormally pushes film when one exposes it at a HIGHER ISO rating.

[jonathan_ratzlaff]

Many photographers shoot portra 160 at either 100 or 80 and ignore any processing changes. Negative film is tolerant enough of overexposure that one stop makes little difference. however the increase in shadow detail is a definate improvement

[andreas_carl]

I routinely shoot Fuji Reala at EI50 instead of EI100 (no adjustment during processing). Gives incredibly fine grain and better shadow detail.

[russell_britt]

You really expose for the shadows and the exposure will be correct. I took a class with Don Blair (Big Daddy) about 15 years ago and he taught this. Some people were using spot meters outside and accordings to their readings he was 3 stops over, thet told he and he said it was not over esposure but correct exposure.Its much easier to take incident readings of the shadows. This only works with print film. I think the newer portra films have much more latatude than the older films.

[peter nelson]

<I>Many photographers shoot portra 160 at either 100 or 80 and ignore any processing changes. Negative film is tolerant enough of overexposure that one stop makes little difference. however the increase in shadow detail is a definate improvement</I><P>

 

My first experience with Portra 160 was in a fashion photography course last summer and the instructor - a local catalog fashion photographer - said he usually shot Portra 160 at 320. I was a little skeptical based on comments like the above, but I have to admit that when I shoot Portra 160 at 160 I sometimes get excessively dense negs and blown-out highlights, so he may be right.

[pete_andrews]

Peter: I suggest that instructor gets his meter checked. Portra 160 is overated even at EI 160, and I'm surprised anyone gets a useable image at all by rating it at 320.

[scott_eaton]

A lot of info here, but a lot it is subjective with some facts here and there. I've spent thousands of hours analyzing and calibrating various neg films for professional print lines, and I'll tell you what I've come to learn over the years.

 

There is a difference in intended results between purposefully over-exposing print film vs shooting it at a speed higher than the manufacturers rating. I base print film speed on the amount of exposure required to build a midtone density that hits a reference film supplied by the manufacturer. Using the toe/heel method will drive you nuts and isn't practical with print films because of the different ways that Fuji and Kodak emulsions handle increasing density.

 

Notorious examples of print films that don't work well at their rates speed are NPH, VPS and to some extent older Reala.

 

Print films that do work well at their rated speed are Kodak Supra 100/400 and Kodak Gold 100. Most of the amatuer films handle well at their rated speeds, expcuding Superia-Reala which tends to prefer being rated at slower than EI 100.

 

Example: Shoot a grey card with Gold 100, and then NPH exactly two stops down. Now measure the density of those frames while subtracting the difference in the clear base. You'll find that NPH IS NOT two stops faster than Gold 100 and NPH will correspondingly suffer if shot at EI 400.

 

The other side of the coin is simply over-exposing print films to alter their inherent picture qualities. 10 years I might have agreed that halving the ASA of any print film will lead to better images. With current emulsion technology that's not the case, and too much over-exposure can get you into trouble, especially with higher contrast Kodak films like Supra. Fuji print films by nature of their built in compensation technology typically like a full stop of over-exposure. Kodak print films like the Portra series work well rated about 1/3 slower that their listed speed, but they gain less advantage than the Fuji print films in terms of deliberate over-exposure.

 

So, what's my point: The problem with rating all print films 1/2 of their rated speed is that doing so may result in several frames of random shots on that roll ending up much more over-exposed than a single stop. A stop of over-exposure is no big deal for print film, and even two stops. The problem is that a frame of print film two stops over-exposed is going to be a bitch to scan later on and throw off the color balance on any automated printer. Guaranteed that shots with proper exposure will have a different print color balance than shots one or two stops over. Most commercial printers can barely slope out a one stop bracket either way in terms of keeping linear color balance.

 

Increasing exposure with print film results in increasing saturation of the dye-clouds in the emulsion, and the net result is a "smoother", and in some cases more saturated color. The drawback is that you'll start to lose detail and sharpness because of halation effects, dye-coupler crossover, and other strange things that happen with more over-exposure. NHG I and Agfa Ultra 50 are two films that could not be safely over-exposed without some obvious loss of image quality.

 

The best way to get around all these variables is to shoot a test roll of any print film at various speeds, take notes of those speeds, and compare the proofs when you get them from the lab. Note where your proofs tend to "even in out" in terms of quality and this will be a good personal EI for that print film.

[ed farmer - mount laurel,]

I really like you Scott!

[pphaneuf]

Scott, you're the man.

[bernhard]

Me too!

 

If Scott would write a daily column in a newspaper, I would buy it everyday.

[daniel flather]

Beauty!