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Film Overexposure Increases (or is it Decreases?) Print Graininess

written by: Dick Dickerson & Silvia Zawadzki

So which is it? The short answer is (predictably): It depends. Two factors are operating here. Increasing film exposure slides all scene elements to positions of higher density on the film curve, and increased density means increased grain. Were this the only factor at work, overexposure always would result in more graininess. But grain also varies with film contrast: More contrast (longer development time) means more grain, and vice- versa. So if overexposure requires pull processing (a shorter development time), this acts to counter the grain-enhancing effect of simply overexposing. This brings us back to the last issue’s column. There Read more »

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All Films Have Similar Overexposure Latitude

Or do they? Check their characteristic curves to find out
written by: Dick Dickerson & Silvia Zawadzki

Excepting hand-held, available-light aficionados, under-exposure is something we tend to avoid like the plague. But overexposure? No problem. All black-and-white camera films handle overexposure with ease. Or do they? It depends on the shape of a film’s characteristic curve. Many photographers, especially fine-art photographers, routinely overexpose film relative to its ISO speed rating. Typically, this is done to capture additional shadow detail in the negative, affording the opportunity to include it in the final print, or not, once it is time to make that print. Two films may furnish rather similar tone reproduction when both are exposed “normally,” based on Read more »

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A Better Choice Than VC Filters?

written by: Dick Dickerson & Silvia Zawadzki

Our previous column described some of the idiosyncrasies encountered when using discrete variable-contrast (VC) filters to manage contrast with black-and-white VC papers. There are alternatives to those filters, notably vari- able-contrast enlarger heads and color heads. But, as described here, these too do not lack for “watch-outs.” VC heads typically incorporate a pair of lamps, each behind a dichroic filter. The filters may be a magenta and yellow pair, or a blue and green pair. Pick a desired paper-grade number from the unit’s controller box and it will select the right mix of light from the two to produce that Read more »

Variable-Contrast Filters– Are They All They Claim to Be?

written by: Dick Dickerson & Silvia Zawadzki

A set of filters with which to control printing contrast is about as basic a tool in the black-and-white darkroom as a pair of print tongs or a thermometer. And that makes them very easy to take for granted. Pull out a number 3 filter and it’s obviously a 3—not a 21⁄2 or 31⁄2—definitely a 3. Or is it? The answer is, naturally, “it depends.” Such filters have been around since the days of Du Pont’s Varigam system and are available to this day under perhaps a dozen brand names. We selected two of the better known, Ilford Multi- grade Read more »

Condenser or Diffusion Enlarger?

The real differences, plus how to make adjustments
written by: Dick Dickerson & Silvia Zawadzki

Condenser vs. diffusion enlarger optics: This is one of the touchiest subjects we encounter; the claimed advantages or shortcomings of one or the other optical system ignite really impressive passions. To be clear, we will differentiate in this column as follows: Condenser enlargers have one or more large, heavy glass lenses incorporated below the lamp house and above the negative carrier and enlarging lens. These condenser lenses are absent in what we will term here a diffuse enlarger. The key difference The singular characteristic of a condenser enlarger is the directional nature of the light arriving at the enlarger lens. Read more »

Do Light Meters See the World as 18% Gray?

written by: Dick Dickerson & Silvia Zawadzki

In a recent column (PT May/June 2008) we discussed average scene reflectance. Our analysis of 150 outdoor images led us to conclude an average scene reflects 12.4% of the incident light, about a half-stop darker than Kodak’s 18% gray card, which is popularly assumed to represent average scene reflectance. But we also noted that the instructions accompanying that card sometimes recommend giving a half-stop more exposure than it indicates, making it the functional equivalent of 13% gray. A very closely related topic we will discuss here is what reflected light meters assume average scene reflectance to be. Surprisingly, they make Read more »

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Does the Choice of Printing Paper Inluence Print Graininess?

written by: Dick Dickerson & Silvia Zawadzki

There are a number of off-the-cuff responses that would seem, on casual consideration, to afford a clear cut yes or no answer to the title question. But the factors that contribute to print graininess are manifold. Below we consider each of them individually to appreciate their interactions and consequences— and to highlight a lesser known but significant path whereby paper choice can indeed influence print graininess. One factor is of course the negative’s graininess. Grainier negatives produce grainier prints. QED. We will remove this from the present discussion by restricting our attention to a single negative printed on various papers. Read more »

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Is 18% Gray a Myth?

The basis for most photographic exposures may be wrong
written by: Dick Dickerson & Silvia Zawadzki

We’ve been intrigued of late by two questions: (1) What is the brightness (reflectance) of an average scene? and (2) How many scenes qualify as average? The obvious answer to the first question is that average scenes are 18% reflective—after all, Kodak’s ubiquitous 18% gray card has served as proxy subject matter for decades. But the card has an odd feature: Sometimes the instructions that accompany it tell a photographer to use camera settings directly as read from the card. Sometimes, however, they say to note those settings, then open up half a stop. That curious proviso, when it is Read more »

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Desaturate: As Good as Convert to Grayscale?

written by: Dick Dickerson & Silvia Zawadzki

In perusing the countless color digital images we seem to accumulate, our eyes are always open for one that would work well in monochrome. We have a tendency, when reviewing a batch of color, to stop every now and then and hit Desaturate or Convert to Grayscale, just to get a quick idea of the black-and-white possibilities. We’ve been using the two commands almost interchange- ably for this, and only recently took a serious look at them—and will never again use Desaturate for quick peeks. The color image shown here, quickly assembled from items in Silvia’s kitchen, is what turned Read more »

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Grain Clumping – Fact or Fable?

written by: Dick Dickerson & Silvia Zawadzki

Coarse-grained images are often claimed to suffer from something called “grain clumping,” which in turn has been ascribed to too long a development time, too high a development temperature, too alkaline a developer, and too long a total wet time, among other reasons. Detailed rationales of clumping describe how individual emulsion grains swim together in the emulsion to form these clumps (doesn’t happen); others claim the origin is development by-products from one developing grain diffusing out and rendering nearby unexposed grains developable (also doesn’t happen except with lith films in lith developers). Still others confuse extreme graininess with reticulation (an Read more »