A Beginner's Guide to Enlargers
©opyright by James Ollinger. All rights reserved.
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Darkroom beginners often ask about different kinds of enlargers and what to look for in one, so I wrote this up. Note that I'm not covering the fancy, high-end enlargers here (mainly because I'm not familiar with them)— but I think that beginners will find this a good starting point toward evaluating enlargers on their own.
An enlarger is really a very simple piece of equipment. It has a head, which is a light source and some sort of method to try and make the light fall fairly evenly across the negative area. It has a column, which allows the head to be placed at various heights away from the easel, allowing various degrees of enlargement. It has a negative carrier, which holds the film (negative or transparency) under the light source. It has a focusing stage (usually bellows), which (when used with an enlarging lens) allows the projected image to be focused. And it has a baseboard or a wall mount that the column mounts to, which holds the enlarger column steady and the head upright. (Note: I've been discussing vertical enlargers, which are the most common. A horizontal enlarger is about the same, except that the column runs horizontally and the image is usually projected onto a wall-mounted easel.)
Just about every feature or variation on an enlarger deals with one of the above parts of the enlarger (usually the light source).
Now let's discuss these things individually.
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The most common enlarger sizes are 35mm, medium format, and 4x5. There are larger and smaller enlargers but they're much less common.
Before you look at enlargers, you want to try and anticipate the largest negative size that you're likely to use over the next several years. A quality enlarger will last decades if you care for it. Even a cheap one should last for quite awhile. If you make accurate forecasts of your photographic needs, you can buy the proper enlarger to fulfill your needs for a long time to come.
If you know you're going to shoot 35mm exclusively, there will be little point in buying an enlarger that will handle bigger formats. Likewise, if you think you're going to try 2 1/4 x 2 1/4 or 4x5 sometime, then buying an enlarger that will only handle 35mm may prove too limiting later on.
If you are going to err, try and err toward a larger size. A given enlarger can take smaller negatives than its maximum size. Thus if you buy an enlarger that can handle 2 1/4 by 3 1/4 negatives, you can also print 2 1/4 square, smaller medium format, 35mm, 35mm half-frame, and so on. But you can't stick a 2 1/4 square negative in a 35mm-only enlarger.
Now a word on the negative carriers themselves: carriers usually hold the negative in place by sandwiching the negative between two pieces of metal or plastic. The carrier holds the negative flat and in the proper position. The carrier has a cut-out window the size of the negative image. Some negatives have glass in the windows and some are glassless. Both have their good and bad points.
Glass negative carriers are usually found in larger formats because the large negative can rest on the glass to prevent sagging. However, roll film can also benefit because sometimes the negatives curl a little. A negative that isn't flat may not produce a sharp image across the negative area.
Glass negative carriers are also nice because they can handle the largest negative they were meant to carry plus any smaller size. Thus you can have one 4x5 glass negative carrier that'll handle all negative sizes up to 4x5 format. Glassless negatives generally can't do that.
There are some problems with glass carriers, though. One is that they can be broken, chipped, and scratched; and they definitely collect dust and fingerprints— all of which may degrade the image. This is particularly true of dust. If you get glass negative carriers, get in the habit of handling them while wearing clean cotton gloves, and get a bottle of Spotone (or equivalent) for the prints.
The worst problem with glass carriers is Newton's Rings. This is a swirl that is caused by the interference pattern of light as it bounces between the glass and the shiny film base. You can solve the problem by using Anti-Newtonian glass, which is not completely smooth on the contact surface of the glass. This irregularity on the glass surface breaks up the interference pattern. Unfortunately, it may be detectable on ultra-sharp prints and large magnifications.
Glassless negative carriers are popular because they're less expensive, they don't have a surface to break or keep clean, and they don't cause Newton's Rings. They don't squeeze the negatives flat, however, which may cause sharpness problems if the negative buckles.
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The enlarger head contains the light source (often called a lamphouse), and there are a number of different kinds. The light source can't just emit light—it has to put out a light bright enough to allow reasonably short exposure times, but not too much to heat and damage the film in the carrier. Just as important—it has to be able to light the negative evenly across the negative area; otherwise the center of the negative (or worse, some other portion of it) will be bright and the edges will be dimmer.
There's also the matter of the color of the light. B&W work uses white light, but color work requires the light to be tinted through filtration. This is usually accomplished in the enlarger head.
If you want to make B&W photos, all you need is a head with a white-light source. If you want to print color photos, however, the light is filtered to obtain a desired color. There are three common ways to filter the light:
If you are reasonably sure that you are going to print color in the future, then seriously consider an enlarger with a dichro head, as they can be useful even in B&W work. Or consider getting an enlarger that can be fitted with a dichroic head later on.
If you think you may dabble in color later on but the vast majority of your work will be B&W, or if you're on a tight budget—get an enlarger with a filter drawer. It's there when you need it and you can ignore it when you don't. Avoid enlargers with no filter drawer unless the enlarger is otherwise perfect for your needs and you're willing to deal with below-the-lens filters.
The lamphouse on the enlarger can't just emit light—it has to put out light evenly across the negative area—otherwise the center of the negative will get more light and the edges will get less, which will cause uneven exposure and a lot of headaches during the printing session.
There are two common methods to handle the problem of even light illumination.Condenser heads
Condensers are great big (big enough to cover the negative) lenses—usually they're two plano-convex lenses with the flat surfaces facing outward and horizontally and the curved surfaces are facing each other and nearly touching. Some (usually better) enlargers have a third lens that can be positioned for different negative sizes, while other enlargers require different size condenser sets for each film format. Different condensers or settings are used to ensure that different sized negatives are illuminated evenly.
Condensers collimate the light—they bend the light rays parallel to each other, which has two effects on the image. The first is that you tend to get a little better acuity and sharpness of the image, since all the light rays are coming down perpendicular to the negative film plane. Unfortunately this can also emphasize defects in the negative and the negative carrier glass—like dust and scratches. Careful handling of the film and the negative carrier and a bottle of spotting solution may alleviate that problem.
The other effect of collimated light is called the Callier effect. When these parallel light beams hit the negative, the light beams get scattered as they hit the emulsion. On low density areas (which will print as dark tones), the light passes through relatively unscattered. But in the high density areas (which will print as highlights), the light rays will scatter more, and the rays won't be quite as intense when they hit the paper below. This increases the contrast of the print a little because the print will be a little lighter in the high values than it was meant to, which may cause blocked highlights. If you compensate the exposure to get the highlights printed properly, then the low values may be overexposed. You can fix that by cutting the development down a little, but may cause a lack of separation in the low values and muddy blacks. (The fix for that is pre-flashing: giving the paper an over-all, brief exposure to plain light, which will change the exposure thresholds in the low values.)
Despite the Callier effect, condenser enlargers are very popular, particularly among hobbyists and beginners, and many people use them (including me, though nobody's going to get my photos confused with Adams's or Weston's) and are perfectly happy with them. Fine art photographers tend to prefer diffusion heads.
A diffusion enlarger has a piece of opaque glass that purposely scatters the light rays, which does two things: it helps provide even illumination across the face of the diffuser (and thus even illumination across the area of the negative), and it provides already-scattered light rays to the negative, thus minimizing the Callier effect.
Diffused light rays, since they're scattered, tend to lower the acuity and grain sharpness a little, and dust spots and scratches are less noticeable. Also, with the Callier effect minimized, the image contrast tends to be a little lower and the highlights get a little more printing exposure.
Diffusion heads generally have one of two light-sources—a tungsten bulb or a cold light unit. Tungsten bulbs work well and they're found on the less expensive units, but they put out a lot of heat, and if the head isn't ventilated well, the negative may get hot and buckle.
A cold light head uses a big tube or a grid to create even illumination, and they run much cooler than tungsten bulbs. The disadvantage is that they're more expensive and they may require special voltage stabilizers and print timers.
For beginners, a cold light machine is probably out of the price range, but a tungsten diffusion enlarger may be affordable. They are an attractive alternative to a condenser enlarger.
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The column of the enlarger holds the weight of the enlarger head, and allows the head to be positioned at a given height above the easel. This is where the "enlarging" comes in.
A good column should do two things—hold the head steady so that vibrations don't blur the image, and it should move the head smoothly up and down the column length. Less expensive enlargers usually have smooth columns and you push the head to the desired height and lock it into position. Better enlargers tend to have a rack and pinion so the head can be cranked smoothly into position. Luxury enlargers offer motorized drives.
The baseboard holds the column steady and gives stability to the whole enlarger. When the head is cranked all the way up, the center of gravity is high and the whole unit will be more susceptible to vibration. A good baseboard will keep the enlarger steady and dampen vibration at all enlarger head heights.
When you check out an enlarger, be sure to see how rigid the enlarger is. An enlarger that rattles or vibrates easily is probably going to be unsatisfactory in use. A good, steady, rigid enlarger will hold the projected image steady during print exposure.
Always check the action of moving the head along the column as well, and see how well it locks into position. If it's difficult to get the head into a given position—especially when making small changes—then it's going to be difficult to crop the image on the easel. If the head doesn't lock down well, then it may get knocked out of position (and out of focus).
Be sure to check how well the column is attached to the baseboard, and how well the baseboard is suited to the weight of the enlarger. There are few things more unsettling than having an enlarger topple over in a heap.
On simpler and less expensive enlargers, the column is plumb vertical. For smaller enlargements that's fine, but at some point as the head goes up, the back edge of the image is going to extend back past the column, which limits how the size of the enlargement. Manufacturers usually get around this by allowing the head to swing around for floor projection (you need to put a heavy weight on the baseboard, or clamp it down to keep the machine from tipping over).
Another common answer is to rake the column forward to that the head travels forward as it goes upward, so that the edge of the image never crosses the base of the column. Oblique columns are typically found in larger, more expensive machines.
On most machines the head is attached directly to the column bracket and that's it. But some heads are attached with an arrangement of bars and springs that form a parallelogram. The whole thing still travels up and down the column, but in addition the head height can be adjusted using the parallelogram while leaving the main column bracket alone.
These enjoyed a vogue in the 1950s and 60s, but mostly disappeared by the 1970s. Leitz used it on their Focomats, and it can be found on many others. An advantage to using them as that the head could be positioned outward away from the column, which solved the cropping problem with vertical columns at high magnification. The chief complaint is that they aren't as sturdy and can't be locked down as well as a direct-attach (no doubt Leitz over-engineered theirs to work well).
I only had one enlarger that had this arrangement, but it was a rinky-dink and I don't want to fault them all for it, but I can completely understand the complaint that they don't hold the head as steady as you might desire.
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Right under the negative carrier and the lamphouse is the focusing stage. It's made up of a lens board and a bellows. The distance between the lens board and the negative carrier can be adjusted to bring the projected image into focus.
Just about any decent enlarger has a rack and pinion focusing mechanism to make focusing easier. Some enlargers may have a motorized focusing unit. Be very wary of any enlarger where you have to push and pull the lens board into focus.
Again, always check the smoothness of the action and how it holds after you take your hand off the knob. If it's too tight, it'll be difficult to precisely focus the image. (I had an enlarger with this problem. It took too much torque to turn the focus knob. I'd get the focus right, let go of the knob, and the knob would turn backward a little and the image would go out of focus. I would have to turn the knob a little bit more than I wanted and let it snap back into position. This doesn't make critical focusing very easy.) If it's too sloppy, the image may slip out focus the second you take your hand off the knob. A good focusing mechanism should be firm but precise, and the lens board should stay exactly in position when you take your hand off the knob.
Auto-focus doesn't mean the same thing in enlargers as it does in cameras. Really it's more like "follow-focus." The idea is that compose and focus the image once, then the enlarger keeps the image in focus as the head is moved up and down the column.
It's a great feature when it works, because trying to carefully crop and focus an image can be a pain.
The problem is how it's accomplished. In most auto-focus systems, the lens stage is directly coupled with a cam that rolls along a track that's located on the chassis. As the wheel turns, it mechanically adjusts the lens stage.
For this to work properly, the curve of the track has to be mathematically calculated and machined to match the lens. Ideally, the track would be matched to an individual lens at serial number level. So it's not just an 50mm f/2.8 El-Nikkor, but 50mm f/2.8 El-Nikkor #2518010. Another 50mm f/2.8 El-Nikkor will be close, but it may not be quite right. And if you have to manually refocus every time you move the head, then the whole thing is wasted anyway.
Companies like Leitz pulled it off, but they demanded close tolerances in their lenses and their tracks. They also charged a mint for it. Most other companies came close but ultimately, auto-focus never worked as well it should have. Autofocus showed up in the 1950s but were pretty much gone by the 1980s. What does that tell you?
Some machines come with rangefinder forcus, which is an aid for focusing the image on the easel. Usually there's a special target you set up and then focus on that. I've never owned one and have no first-hand experience, but a) I've read comments that they're better in theory than in practice, and b) like autofocus, they appeared in the 1960s and were mostly gone by the '80s. That suggests to me that they weren't very good.
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A lot of people buy a decent enlarger and then skimp on an enlarging lens. If you can, skimp on other things and get a good enlarging lens. A camera may take a bunch of lenses for varying situations, but an enlarger will probably only need one (or one lens per negative format you use). An enlarging lens is an investment—a good one will last many years if it's cared for, and it can be used even when you change enlargers at a later date.
A good enlarging lens is important because it's the part that does the important work of forming the image. A mediocre or a poor lens may have unacceptable light falloff at the edges, it may be unsharp at the edges (or worse, unsharp everywhere), and may reduce the contrast. It's one thing to choose to make your images unsharp—but it hurts to settle for unsharp prints because of a poor lens.
Some people ask if a camera lens will work on an enlarger. Yes, it can: but it won't work as well. Enlarging lenses are flat-field lenses—they're optimized to project a flat image sharply. A camera lens is optimized for three dimensional scenes. Camera lenses can be used if : a) you're in the field and you need the camera lens to do double duty, or b) you're on a seriously tight budget. Otherwise, I advise buying a regular enlarging lens and be done with it.
I also advise buying as good a lens as you can reasonably afford. You don't have to take out a second mortgage to get a good one—and it'll be a better investment than a lot of other things if you do much printing. A decent enlarger with good optics is capable of making sharp prints. A great enlarger with a poor lens is probably going to make poor prints.
Many people write and ask if Brand X Model Y lens is any good. Years ago, a man named Ctein wrote an enlarger lens buying guide in the now defunct Darkroom magazine. If your local library or camera club has back issues, get a hold of the January 1989 issue and read the article. It's also in his book Post Exposure.
There are three big companies that make quality enlarging lenses (there are other companies, but these guys are the big names): Nikon, Rodenstock, and Schneider. Unless the lens itself is defective, any lens by these three companies is quality. Some of the lenses may be better than others, but I don't think you can go wrong buying them.
Generally, the more elements a lens has, the better it is. Quality lenses usually have six elements. Mediocre lenses have four. And cheap lenses have three.
Nikon makes the El-Nikkor line of six-element lenses. Rodenstock makes several—their budget (four element) line of Rogonars and their six-element Rodagons. Schneider makes a cheap-o line of three-element Componars, budget grade four-element Comparons, and their quality six-element Componons.
Beseler Photo sells a line of lenses under their own name. The Beselers are three element. The Beseler-HD lenses are far more desirable six-element.
Occasionally you may see APO or apochromat used when describing a lens. An apochromat lens is considered to be highly corrected (and thus sharper).
Enlarging lenses, like regular camera lenses, come in different focal lengths. You want to select a lens that will work well with the negative format you are using. If you select a lens that is too short, the projected image will be very wide and you'll have the enlarger head down low to make small-magnification prints, and the bellows may not collapse far enough to be able to focus the image. If the lens is too long, the enlarger head will have to be pushed high to make large magnification prints, and the bellows may not extend far enough to focus the image. Also, a given lens can only cover a certain size negative. You can put a long lens on a small negative, but a short lens may not cover a large negative.
Here's a very general guideline for lens sizes and negatives:
|Negative format||Use Lens focal length|
|35mm||50mm - 75mm|
|2¼ x 2¼ (6x6)||75mm - 90mm|
|2¼ x 3¼ (6x9)||90mm - 105mm|
|4x5||135mm - 150mm|
|5x7||180mm - 240mm|
|8x10||240mm - 360mm|
Whenever you look at a lens, be sure to check out:
Don't pay a lot of money if the answers to the above questions are unsatisfactory. There are a lot of lenses in the world. If you think a lens is bad or suspect, find something else.
After you buy a lens, run print tests on it. Get a super-sharp negative (if you have one) and make a test print. Is the print sharp? Are the corners sharp? Check the light falloff on the edges.
If you have an enlarging exposure meter, check the marked aperture settings to see if they're accurate. My first enlarging lenses were Cheapos with nifty click-stop f-stops. I could open and close the lens in the dark by counting the clicks. There was just one little problem—if I changed the aperture on the lens, the exposure didn't always turn out the way I had predicted. This was particularly true if I changed the enlarger head height and calculated the proper exposure settings for the new head height. Later on, when I was checking the enlarger out for some other reason and was going crazy because the meter readings weren't consistent, I found out the lens aperture click-stops were off. One click stop didn't necessarily open or close the diaphragm a full stop. And the click-stops themselves were very sloppy—I couldn't open the lens a stop and close it back down and get the original reading! Lessons learned: 1) buy quality lenses. 2) Always check the lens aperture markings for accuracy.
Bad lenses = frustration = expensive paperweights.
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In order to make a sharp print, the enlarger ought to be in alignment. This means that the baseboard (and thus the easel), the lens board, and the negative carrier are all parallel to each other, and that the light path goes right down the middle of the negative and right down the middle the lens and hits perpendicular to the baseboard plane.
Most good enlargers are going to have adjustment screws so that the enlarger can be aligned. Cheap enlargers won't.
When you buy an enlarger, the first thing to do is to align it or have someone do it for you. If your enlarger came with instructions, it should tell how to do it. If not, it shouldn't be difficult to figure it out. If you're not mechanically inclined or you don't have decent tools (you'll need a good bubble level—though there's a company that makes an alignment tool that works using a beam of light and a mirror), get someone else to do it. An out-of-alignment enlarger may not focus the image properly at any or all head positions, and the light illumination may be uneven. I know I'm beating this message into the ground, but there's no point in buying a good enlarger and a quality lens to make bad prints simply because some adjustable plates are askew.
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It's a buyer's market out there, since everyone's going digital. My opinion on things to consider if you're just starting out:
So does that mean you should buy a 4x5" (or larger) enlarger even if you're only going to print 35mm? Not necessarily, but there is a possible increase in quality. Considering the very large increase in bulk and weight every time you go up a format, I wouldn't exactly advise buying a 4x5" if you're only going to use 35mm. But definitely consider a 6x6 or 6x9cm machine. If you plan on doing work with medium format, definitely consider a 4x5" enlarger, and so on. And conversely--if you find a 6x9cm or a 4x5" enlarger you think is wonderful but hesistate because you know you'll never need to go that big--you can still justify it from a quality perspective.
If you want more information on enlargers, I suggest:
Ansel Adams: The Print. This is where I got and confirmed the bulk of my information. It is the standard photography text against which all others are compared. The book isn't as densely illustrated as others and it can be intimidating for beginners, but Adams's writing style is very lucid and readable, and I highly recommend looking at it at some point.
J. Ghislain Lootens: Lootens on Photographic Enlarging and Print Quality. This slim volume is long out of print but shows up at the used bookstores from time to time. It's out of date (my 7th edition is from 1967), but much of the information is still useful. It is a very readable, useful book. If you find a copy at a used bookstore or photo shop or library, get it.
Ctein: Post Exposure. It's really an advanced text, but very much worth a look when you are ready to expand your expertise. Ctein wrote the aforementioned article on enlarging lenses, and he also discusses enlargers in this book. Also see his website: http://www.plaidworks.com/ctein/.
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