How did they post process before Photoshop?

Question

So, yes, I'm intrigued as to how they post process pictures before Photoshop (or computers, for that matter) came about. Or is post processing a by-product of the computer revolution?

My understanding of film photography (all from the film equivalent of a point-and-shoot we had when I was a kid) is that light burns into film then film gets developed. And, well, unlike bits, your end-product is tangible and "permanent", for lack of better term.

I'm woefully ignorant about film processing but I guess this is where the post-processing takes place? How do they tweak color temperatures? Remove red eyes? Retouch skin blemishes? Do they use special dyes/inks to achieve better colors/contrast?

Answer 1

There was quite a lot you could do, actually.

Let's start with the basics -- overall exposure and contrast. This is something that anybody who had a darkroom would have done as a matter of course. Photo papers come in different contrast grades, and some black-and-white papers were variable contrast, reacting differently depending on the colour of the light you used in your enlarger. You could do a lot about changing the overall exposure and contrast merely by changing the time that the paper was exposed and the contrast grade of the paper. Changing colour temperature in colour prints was a matter of changing the filter pack (or the settings on a dichroic light source). Small shops would go by a keen eye; large labs would use a colorimeter.

Photoshop (and similar programs) have tools called "dodge" and "burn", and these come straight from the darkroom. You would use a shield to "dodge" light from hitting the paper, or a larger card (often with a hole in it) to let extra light "burn" the paper. This would let you make local contrast and brightness changes.

"Masking", including "unsharp masking" also comes from the darkroom. Contrast masking would be done by sandwiching your negative together with a piece of unexposed film (usually something with a very low sensitivity) and exposing the film through your negative. That made a weak positive image, which you would then develop with low contrast. Sandwich the two together again, and your shadow areas got some extra density, bringing the overall contrast down. Put a piece of clear film between the two when exposing the mask, and you get an unsharp mask, which could be used to enhance the edges in the image (the same way that the Photoshop effect works). You could also paint directly on the mask or bleach out exposed areas in order to remove areas of the image.

Retouching involved using pencils or dyes on both the negative and the print. Since you can only controllably add density (you can put more black or colour on a little at a time, but bleaching is more-or-less an all-or-nothing technique), you would lighten areas by retouching the negative and darken them by retouching the print. Red eye correction was usually done on a print using a cyan dye pen and a careful dotting technique. It was all hand work, and it was enough of an extra-cost option that most people wouldn't have bothered with it for their snapshots.

Then there were wholesale changes you'd make by airbrushing and collage. That was normally done at a very large size and then rephotographed to minimize the appearance of the handiwork.

Add hand-tinting black and white pictures, using ortho/litho film to transform a continuous tone image into line art or bas relief and so forth, and the arsenal of tools and techniques gets pretty big. It was nowhere near as easy as Photoshop, and there wasn't so much an "undo" as a "start all over again", but we weren't stuck with what you could get at the druggist's by any means.

Answer 2

It depends on what you are talking about, there are really two different types of photo production -- for publication and fine art print. Back in the day, more people used the fine art print "workflow" and the publication workflow was mainly just for people who worked at newspapers, magazine or made reproduction prints. Today, essentially everyone is working in the production workflow and fewer people in the art print workflow. Note, I've a newspaper technical background, so some of what I'll say is colored by that.

Fine Art Print: This is also the basis of all of the other workflows (except maybe where folks were reproducing slides, I'm a little fuzzy on early color reproduction -- I've never worked at a newspaper that did many color pictures before computers). This is your basic darkroom photography, where you projected the film onto a sheet of light sensitive paper and then ran it through a couple of chemical/water baths.

For black and white work you either stocked papers with different contrast curves or used variable contrast paper that changed contrast depending on the color of light used to expose it (so you had to stock those filters). The nice thing about VC paper is that you could have different contrast curves in different parts of the image by masking the image (physically, with cardboard or something!) and exposing different parts of the image with different filters. Dodging and burning were literal, using more cardboard or little tools to either hold light back from part of the image or give extra light. All other retouching would be with a paintbrush or airbrush -- although some people would actually work on the negative itself.

For color work (and again, I don't have much experience here) color temperature would be corrected by colored filters. You would need quite a few and it was very tedious to get things right.

Publication: Two ways to go here. For black and white work, you could cover a sheet of high-contrast paper with a screen with little gaussian dots in it. This would change the artwork into a series of dots -- larger dots for the dark areas and smaller dots for the lighter areas. These images would be worked into a paper representation of the page and then shot on a very large camera which would produce a piece of film the size of the page. The negative would then be burned onto a printing plate. We are talking 50s-60s technology or so.

For color work, you would still start with a print still (if memory serves) but you would photograph it several times using different filters on the camera to get cyan, magenta, yellow and black "separations".

Hopefully this explanation isn't too far off or confusing, but the process was a lot more difficult, involved smelly chemicals, dark rooms and was hard to reverse. And I feel very old just knowing all this :-)

For a more in depth look at this (especially from a black and white standpoint) I recommend Ansel Adams' book "The Print".

Answer 3

Lot of the basic ideas have already been covered, but there was a whole scale of various tricks you could use. For example, you could sharpen your prints by developing them in a completely stationary developer, instead the usual process which involved constant agitation of the paper in the developer. The problem with that was that large dark areas could end up underdeveloped, but it was a useful technique for making a photographic reproductions of printed materials. An extreme version of this technique, where you would briefly soak your exposed paper in the developer solution, take it out, and squeeze excessive developer from it with a roller, and develop the print in an extremely thin layer of solution, would create an effect similar to an edge detecting algorithm.