Metering yo ur color neg-

[TSSPro]

Just wanting a little bit of insight without having to burn too many rolls trying to find out how film stocks react, but I have heard a myriad of thoughts on optimizing exposure of color neg images based of how you rate them.

I have been rating a majority of my film at box speed. I know that labs like H&H used to print the densities on the back of your proofs and optimally they should have fallen in the ~30ish range (Not sure how they measured them). And because of that one of the photographers I work with would rate his vericolor II at 64iso to get the optimal densities for H&H proofs.

Manipulating black and white and chrome this way isnt new for me, but in color neg i've never tried.

As a general practice, are most people overexposing their color neg or rating it lower than box speed to gain an advantage?

[nsouto]

With modern colour neg film, I would not recommend overexposure as a "general practice".

Having said that, it has its applications. For example, in very contrasty situations and where you need to preserve some detail in shadows it may be a good idea to overexpose slightly. I do this often with colour negative film and it works well.

But we got to be careful with the terminology here. Exactly how does one "overexpose slightly"?
A number of ways:

1- set the meter's ISO to slightly lower and take a normal averaged reading.
2- keep the meter at rated ISO, measure the light shadows and put them in zone 4 (equivalent to +1 overexposure from mid-grey).
3- if using on-camera meter, set the exposure compensation in the camera to +1 or thereabouts and take a matrix reading.
4- go full manual in the camera, leave the meter on rated film ISO and use the camera as a spot meter as in 2 above.

and so on. The sky is the limit, really.

Think of it this way: you want to increase the density of the exposed image in the shadow (less dense negative) areas of the image.

This makes scanning easier as well as lengthening exposure if using optical printing.

And it gets rid of the "spotted colour" noise effect some colour negative films show in low density areas.

Just like in b&w, be aware that excessive over-exposure will need extra compensation at development time, otherwise light areas (very dense negative) will blow out in the positive.

It all depends on how you are going to process the image and the nature of the image subject itself.

Hence why I am against a "one size fits all" approach of overexposing everything with colour negative.

Use where needed and with full awareness of why, rather than as a "recipe".

[pellicle]

Hi

firstly before you start discussing about "box speeds" you need to understand how that system of rating works. Do you now?

Lets side track that discussion and I'll recommend you read my page here. I recommend the whole article, but definitely it may start your interest by starting there at C-41.

you don't mention (or I didn't see) how you are metering, are you using an in camera meter; if so is it spot / matrix / evaluative?

I think that the easiest way is to consider the actual system and keep in your mind what that will imply ...

Negative means that the darkest areas of your picture will not supply enough light to leave any mark on the negative ... meaning it will be unexposed. Conversely the brightest areas will make the darkest marks on the film.

Now here is where you need to think out of the digital 9 dot array. The dark / dense areas do not respond linearly to light. So you don't get clipping, but it does end. The old guys think in terms of shoulders, I think in terms of exponential data compression algorithm

So where its "linear" you put in 1 and it writes 1, 2 and it writes 2 ... up on the "shoulder" of that curve you put in 5 and it writes 5.1, 6 and it writes 5.3 7 and it writes 5.31, 8 and it writes 5.311

So as you give your negative more exposure the dynamic of your image falls off but the image remains (perhaps just a little flatter).

Now as you tend towards under exposing (as mentioned) the ability of you to pull useful image information from your film gets harder. Think "base fog" and trying to see something in the fog.

Thus in this area you'll noise from the media (the perfection of the recording of R G and B levels will be out) even though you'll be in a place of your scanners ability to discern level information very delicately.

up in the dens area (hilights) you'll get noise again because the density of the C-41 (especially the blue channel) can be quite high. Some sample histogram from the scanner driver:


Perhaps that blog post may be worth your reading too.

Lastly (depending on the scanner you use) you can get different results with different scanning strategy, that however is a different question.

[TSSPro]

Wow- I wasnt exactly looking for anything too technical, but rather an "In my experience..." sort of response.

Thanks for all the info.

I have wondered this for a while, but in a thin neg, the reason for a generally cloudy looking c-print, or unedited scan, is the orange mask getting in the way? Or rather, does the orange mask inhibit a prints d-max when the exposures linger toward the bottom shoulder of the response curve?

Both responses mentioned methods of metering. For things within arms reach its indecent, and those things which are not at arms reach, a 1deg spot. I'm normally good about assigning zones in a scene to get my exposure and a vast majority of the time my print values match my pre-visualized image.

Thanks again for the input and the links.

[pellicle]

Wow- I wasnt exactly looking for anything too technical, but rather an "In my experience..." sort of response.

ok ... in my experience I let the built in camera meter do its job, I only EV compensate with dramatic subject matter such as snow.

Stuff like this is normally done in Manual with sunny 16



up to +2EV over and its still fine.

Spot meters are deadly weapons in the wrong hands (not saying yours are). Love them for my black and white sheets, totally hate them for chromes (I've been using a Pentax digital spot meter for decades).

As you probably know all meters work on something called 18% grey and debate about 12% grey is a dicey area. If the scene fits within the negs straight range then snuggle it up as far as you can towards the shoulder to get better shadow details.

Using 4x5 I set my camera (my digital camera) on the rated ISO of the film and then base the rest on what I get (histogram) and knowledge of what the film does with this or that sort of thing.

[TSSPro]

Thanks for all the input and info.