Want to Try Double Exposures? Forget Everything Else You’ve Read

Want to Try Double Exposures? Forget Everything Else You’ve Read

Double exposures, when they’re done well, are incredibly impressive. The literature on how to do them is fairly limited, but here, I'll explain how they work and how they're done.

How to Make a Double Exposure

If you’re doing this on digital, there are two ways that I’m familiar with. The first requires your camera to be capable of doing in-camera double exposures. If possible, there is typically a setting or an in-camera application to assist with this. The second way is really simple and done in Photoshop. If you're going the Photoshop route, take two images of equal size (or at least make them equal size) and open up them up as two layers in the same document. Set the blending mode to "Screen," and you’ve got yourself a double exposure. 

Shooting film is a different story. If you happen to have a camera that has a built-in function for doing a double exposure, you’re fortunate. Most film cameras do not have this function, but some do. Of my personal camera collection, my Nikon F100 and Mamiya 645 Pro TL have this capability. My Nikon F2 and Mamiya RB67 do not have a built-in function for this, but are still just as capable of it. For the latter example, it is easy enough. The Mamiya RB67 has two different levers, one for cocking the shutter and another for advancing the film. For it and any other camera like it, after taking a picture, you simply cock the shutter and don’t advance the film. 

If you have a film camera with a mechanical advance that cocks the shutter and winds the film simultaneously (i.e., you have to advance the film yourself with a lever), you may or may not be able to take a double exposure. For many film cameras (my Nikon F2 included), there is a button on the bottom of the camera that you have to press in order to rewind the film. For those cameras, you should take your photo, and while pressing the winder release (button on the bottom of the camera), you “advance” the film and cock the shutter.

If your camera automatically advances your film and does not have a built-in function for double exposures, I doubt double exposures are possible without entirely shooting through the same roll twice. Such is the case with certain Pentax 67s and my Fuji GA645. While on the topic of shooting through the same roll twice, it is a fairly common method and can be fun if you’re the kind of person that is pretty carefree about their photographs. If that is what you decide to do, I would suggest attempting to find a way to have the exact same starting place on the film both times you intend to shoot through the roll. Otherwise, the likelihood of not having any of your exposures lining up is pretty high. 

What Is a Double Exposure?

To preface this section, the initial explanation of how a double exposure works is not technically correct. Why on earth would I provide an explanation that isn't totally correct? Great question! The answer is because the technical answer is a great deal more complicated. So, while I hate to start off with a hand-waving explanation, it's what I'm going to do. Following the (arguably over-) simplistic explanation, I'll provide a brief dive into a more complex but more accurate explanation and will perhaps at some point do a much deeper dive into how this works. 

The easiest way to mentally process a double exposure is to think of it in terms of black and white photography. If you consider an image to be a very dense grid with values from black (completely unexposed) to white (completely exposed), a double exposure is the process of placing two images on top of one another and then, in combination, taking the lighter value (more exposed) from each cell. To illustrate this concept, I’ve come up a two simple example that are not attractive (at all) but it gets the point across.

Image 1

Image 2

The "Double Exposure"

Images 1 and 2 are simple screenshots of Excel file grids with a heat map applied to them. The resulting "double exposure" is the combination of the two heat maps. For each cell of the two exposures, the larger value (i.e., the more “exposed”) is kept. While it may be difficult to see, this concept is illustrated with the numbers in the cells. As can be understood from this, the order in which the photos are taken doesn’t matter. This can also be seen in Photoshop by simply switching the order of the photos. Indeed, a double exposure is just one specific case of the more general concept of multiple exposures, and the same holds true regardless of the number of exposures.

If you've read up to this point, you've probably wondered one of two things. If you're wondering how this explanation is overly simplistic and not technically correct, you're in the same place I was in when I first started doing multiple exposures and had no one to help me think through the specifics. If instead, you're wondering how the above could possibly be correct — that, in fact, why am I not actually doubling the values rather than keeping the higher value? The answer is that while technically you actually sum the light intensity (input), you do not always double the response to light (output). The response to light intensity differs between digital and film.

Response curve of Digital and Film

The response curve to light for a digital camera is linear (i.e., double light input = double response). As such, for the above example using Excel, you would simply add the numbers in each cell to determine the final image lightness in the sensor's response. Film, however, does not respond to light this way. The difference lies in the response curve. Film's response to light is logarithmic: this is why film can handle such a large degree of overexposure and why reciprocity failure exists. As such, doubling exposure (input) will not translate to doubling the image's response. Further, while a digital camera responds to multiple exposures is additive, film is more likely to adopt the light intensity from the brighter of two images. 

For those that are interested, I will try and put together a more thorough explanation of how both digital and film respond to multiple exposures. For this initial article, however, I hope you find the above examples satisfactory. If you're a film photographer and have stayed on this long, hopefully, the next section will shed a bit more light on this topic. 

Biggest Misconception in Film Double Exposures

The largest misconception I come across as it pertains to making double exposures on film is that you simply shoot two exposures that are both underexposed by one stop. Admittedly, in theory, this makes sense. Shooting 1 stop underexposed equates to half of the light hitting the negative for two exposures. In other words, you’re taking two exposures, each with half of the light needed for a neutral exposure. This results in one solid neutral exposure. As much as this particular technique has validity at face value, I’ve tried it over and over and have rarely liked the outcome. In theory, it works well, but I don’t think it works particularly well in practice. If you already shoot film, you’re probably well versed in how much overexposure it can take (sans slide film). As such, why aim for a neutral exposure when you can easily shoot 1-2 stops overexposed without much, if any, adverse results?

Low Hanging Fruit

In general, I’ve found that one neutral exposure of a mid-to-low contrast scene mixed with a high contrast scene make for the easiest successes. For example, the most common types of double exposures I see involve the silhouette of someone or something with a second image there as texture. Secondly, the mixture of a portrait with a high contrast scene (think strong light source or a landscape at dawn or dusk) make for great shots when they’re done well. What makes them “done well” you ask? It’s all about proper framing. High contrast landscapes can make for nice images too. This brings me to the double exposures that I generally find most interesting and most difficult: shooting two portraits together. I would suggest having one shot be a silhouette and the other a neutral exposure. Either way, it's fun to play around with them regardless of the subject. 


Are you a fan of multiple exposures? If so, please share some of your work below. 

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49 Comments

Previous comments

So if I'm reading this right you are saying shoot regularly and double expose? The photo attached was on film and to your point probably have been better exposed and eliminated the background with the books and lightened the silhouette if it were shot with normal metering.

James Madison's picture

I've used PS to create multiple exposures before but only with photographs taken with my digital camera. For film work, it's all done in camera. If you had a slightly higher contrast silhouette, you have eliminated or at least really washed out the books. That said, I think it looks good. Thanks for sharing!

My question was, are you suggesting not to stop down the exposure or speed and shoot two normal photos in camera and over expose them?

I guess I'm confused by your response. One section of this article is titled "The largest misconception I come across as it pertains to making double exposures on film is that you simply shoot two exposures that are both underexposed by one stop." I know double exposure is done in camera and your response suggests you only do double exposure in PS.

Point being, which is it? It's extremely misleading to suggest doing something on film when you've only done it in PS and are providing PS photo examples and leading readers to believe it was done in camera on film.

I'm genuinely intrigued by the insight you're trying to provide, but it's very contradictory.

James Madison's picture

I apologize for my response not being concise enough - I use PS to make multiple exposures if and only if I'm putting together photos taken with a digital camera.

For all of my film work (which make up all of the photos in the article except the first one) I do everything in camera.

To your first question - yes, that is what I suggest. The vast majority of literature out there suggests shooting one stop below a neutral exposure for a double exposure (i.e., one stop down for two images if it's a double exposure). I am arguing to not do that. There are even times where I will deliberately overexposure one part of a multiple exposure if I think it will achieve the correct end goal. Two examples of this are the lead image (black and white at the head of the article) and the photograph of the gentleman with the valley of skyscrapers inverted. Particularly for the second photograph, I wanted to make sure that the "valley" was blown out so I found a high contrast scene, metered for the darker parts of the buildings to make sure what I wanted blown out was indeed blown out.

If I'm still not answering your question, let me know. Apologies for the confusion. You can also refer to the short exchange with Adriano above where I acknowledge doing multiple exposures in camera and not always having the best luck.

-MH

All good! I was truly confused. Don't mistake my directness for lack of admiration I just wanted to ensure I was reading the responses correctly. 😁

"Madison is a mathematician turned statistician based out of Columbus"
This made me smile as even without seeing the mini bio I could have guessed that from the article.

No offence but I think you are overthinking this, and I'm not sure misconceptions come into things, I have been shooting doubles and triples for as long as I have been hold a camera and I have never once thought the process through, just gone for it either frame by frame or by shooting a roll then reloading.
I certainly haven't considered exposure other than what I'd do to take any picture.

For me the double exposures are fun, that's the point, if I had to engage my brain too much when planning them that fun would be taken away, see something, shoot it, rinse and repeat :)

The shot below is a triple of my wife, taken using a Yashica Mat EM with a loose theme of "someone on my mind"

Just enjoy...

James Madison's picture

Ha! I suppose it's difficult to suppress my nature. Admittedly, it is the mentally engaging aspect to multiple exposures that makes me love them so much. I could see though that for someone else it could take the fun out of it. So long as you've done it and enjoyed it, I'd say the approach and intent is irrelevant.

Love the triple exposure! Well done!

ashley Barnard's picture

first time I have tried double exposure think it came out ok. canon 5d MKIV

James Madison's picture

This is fantastic! It actually reminds me a lot of a self portrait double exposure I did. Well done!

Tony Brandstetter's picture

Its been a few year working with layers, I have found it is an exciting new approach to photography

James Madison's picture

It's an interesting shot! What exactly am I looking at?

Tony Brandstetter's picture

Thank you James, I apologize for not listing details. Here is the original image shot with an Android 9 cell phone (aka: smart phone). The image was taken in artificial light, produced with 2, 100 watt conventional light bulbs. Next, I placed a Grunge blurred painted background, multiplied the layer then placed a 8 on the brightness. Continuing, I distorted the image with a diffuse glow, grain was set at 0, glow amount was set at 12 and clear amount was set at 19. I then reduced noise to smooth out any left-over grain.
Next I applied a rust texture photographed with a Sony Cybershot, focal length is about 8mm, I placed this image over my cured portrait, positioned it than multiplied that layer with a 10 or 11 brightness, I hit it again with a diffused glow to show separation from the layer to the face.
Since this was shot with a phone I had to reduce the size in order to gather the lose pixels.

I then placed it in the oven at 450 degrees, for 2 hours basting every half hour, let stand for 10 mins and served with a chilled chardonnay.

This is my take on double exposure (I have a series of the event). It also made me some money.

James Madison's picture

These are awesome! I particularly like the first and third shot. Well done!

There is more to double exposure than a full frame double. I used to do half frame double exposures by masking part of the scene for one exposure, and masking another part for the second.

Also, quite a bit of my double exposure work was done in the darkroom under the enlarger. That way, I could play with exposure control, or even sandwich negatives together.

Finally, double exposure can also be done using bulb, and a strobe. Many of my night images were double exposures done at night. Some call this light painting, but that is a slightly different thing, (or very different thing, depending on what one is referring to as “light painting”).

Today, I rarely do double exposures, but when I do, it is usually in camera. My camera gives me three ways of doing it; bright, average, and additive.

In Bright mode, only the brightest part of the image is used, precisely how you explained it in your “over-simplified” false explanation, which, in this case, is spot on! In bright mode, one will never get an over-exposure, but a high “black point” is likely.

In Average mode, the pixels will record the average of the exposures. This will be the same as sandwiching negatives in an enlarger. In average mode, one will never get an overexposure, but a high “black point” is possible.

In Additive mode, it will work precisely as you say it doesn't work, adding the values together. In this mode, one might end up with an over-exposure, and a high “black point” is likely.

Yes, multiple exposures reduces your contrast and DR.

So, with the reciprocity failure thingy, how to calculate the exposure for film? One, ignore it. it really is not that big of a deal. Make sure the sum of the exposures add up to full. Two, Ignore it for a double exposure. Expose both frames properly. Three, don't ignore it. Instead, make sure that the sum of the exposures totals at least ⅓ stop to 1 stop above full. E.g., for double exposure, each exposure is -½ stop, for triple exposure, each is -1 stop, for quadruple exposure, each is -1⅔ stop, etc. (I think my maths is wrong, but the principle is sound. It has been a while since I did film).

Also, multiple exposures can be used for other purposes, when a tripod gets involved.

christopher james's picture

ah heck yes good tips I love making these! heres one from last year

James Madison's picture

That's a beautiful double exposure! Thanks for sharing!

Anastasia Ermolenko's picture

Iceland. Medium format film

Anastasia Ermolenko's picture

Medium format film 🎞