Thick? Thin? Density? [development]

[climbing_vine]

So as someone who hasn't developed their own, I'm always left wondering what "density" is in a negative, all this talk about "thick" and "thin". Sometimes one is better, sometimes the other?

Feel free to tell me to flippin' google it (which I will be doing regardless), but I'm curious to hear it from some of you first-hand, as there are a number of people here whose comments I've read for quite a while. Gives a bit more context than random web sites.

 

[kaiyen]

the silver is exposed to light, then developed. Only the silver that has been exposed will react with the developer. The fixer then removes all the unexposed and therefore undeveloped silver. So "density" refers to how much silver is in the negative still. A frame with more exposure will be denser, since it will have more silver in it.

A thin negative is a low contrast negative - no really dense areas, no areas that are fairly clear. Thick is the opposite.

 

[Al Kaplan]

Brian, they're terms only used by select members of a secret society, but the membership is dwindling due to the relentless assault of billions of wild pixels...well, that's almost true!

Density refers to how dark a negative is. A thin negative lets more light through, and is usually thin due to underexposure. A thick negative doesn't let much light through, probably due to over exposure. When you look at negatives you have to factor in what the subject is, though. A bride against a white background will give you what looks like a thick negative but it'll print fine just fine. The negative is thick because it's a photograpoh of a light colored subject. The opposite is true if you're photographing the proverbial black cat in a coal bin.

What you're striving for is a negative with enough exposure to retain detail in the shadows without losing the highlights, often called blown highlights or blocked up highlights.

With most scenes you'll have as bit of latitude here, and a stop over or under will still give you a printable negative, but generally overexposed black and white negatives result in grainier looking prints.

 

[Roger Hicks]

Dear Brian,

There are many euphemisms and colloquial terms for both density and contrast. High density (low light transmission) is also known as 'thick', 'meaty', and in extreme cases 'bullet-proof'. Density depends on exposure: more exposure = more density.

High contrast used to be known as 'plucky': contrast (for a given subject) depends on development: more development = more contrast.

As a general rule, generous exposure (a denser negative) gives better tonality for wet printing while skimpy exposure (a thinner negative) is easier to scan.

In both colour and mono, more exposure = lower sharpness, but more exposure means that grain will be bigger with conventional mono, but finer with colour neg or chromogenics.

This is why film speeds are not an absolute, but a working compromise.

You may find the following of use:

http://www.rogerandfrances.com/photoschool/ps neg density.html

Cheers,

Roger