UK Passport Photo Tutorial

You want a photograph for an ID. You own a DSLR (or other controllable) camera, and it’s easy to get photographs printed online. Why then should you pay over five pounds for four photographs, when you could pay 5p (at best)? The answer is that it needs a little bit of effort. This tutorial is to guide you through making a good, acceptable, cheap, correctly dimensioned photo suitable for identity documents. Surprisingly, while I found many casually written tutorials online, I didn’t find one that dealt with all the details, which do make a difference. These instructions are for UK passport rules, but I would imagine that other countries are very similar.

First we need to find out what the output we want is. The identity and passport service give the following requirements for the two photos they require.

  • Identical. Easy, we’re going to use the same photo multiple times, so they are guaranteed identical.
  • Colour.
  • Taken against a plain light grey or plain cream background.
  • 45mm x 35mm
  • Head must be centred left-to-right.
  • Head must be between 29mm and 34mm in the photograph. (This is more conveniently expressed for our purposes as between 65% and 75% of the total height).
  • Eyes must be positioned to be slightly above centre, top-to-bottom.
  • Free from shadows.
  • Printed on plain white photographic paper
  • Some other obvious stuff (eyes open, no hats, sunglasses, or hair over your face).
  • No red eye.
  • Neutral expression.
  • Ideally you should have no glasses on, which is good, glasses can cause us photographic difficulties.

They offer the following template:

template
We’ll sort out any minor positional problems in post, so your first job is to get a usable photo. This should be easy enough. You’ve got as much time as you want, and can take as many as you want. Here’s what sort of settings you should be using.

  • Equivalent focal length of around 80mm. That is to say you should zoom in a little and step back. Wide angle lenses will produce photos are at the very least unacceptable to the subject (since they will look distorted, with a big nose and chin, and fat cheeks – regardless of whether they actually have a big nose and chin and fat cheeks), and at most unacceptable to the identity authority. A longer lens will flatten perspective, and give a more flattering (and neutral) photograph.
  • Camera-to-subject distance of between 1 and 1.5 metres @ 80mm equivalent focal length. When framing your subject, bear in mind that a bit of flexibility for cropping, reframing, and altering aspect ratio will be beneficial later, so don’t try and fill every last bit of the frame with the subject’s head. Try and capture head and shoulders, with the total vertical space used by the head being around 50% of the frame (yes, as little as that).
  • Make sure you aren’t looking down or looking up to the subject. They should be able to look horizontally outward directly into the lens, with the lens at, or slightly below, eye level, and parallel to the ground.
  • You are going for a well lit face with no shadow thrown by the head onto the wall, and no shadows on the face. That means as evenly lit a subject as you can manage. That means big light sources, directly in front of the subject.
  • The ideal lighting would be you with the camera in front of an enormous window, during daylight hours. Your back to the window and your subject directly facing the window, in a room with plain cream walls, with their back about half a metre from the wall (although this doesn’t matter much, you can stand them with their back right against the wall without much difficulty). Two shoot-through umbrella flashes would be best, placed either side of the camera, this will remove all shadows. A ring flash would be good too. A window in a house that isn’t a stately home will likely not be big enough to remove all shadows, so you may need to reenable the on camera flash to use as fill – however, set it to very negative flash exposure compensation (-2, say) to avoid red eye.
  • Keep the ISO low, 100 or 200 to keep noise to a minimum.
  • We want the whole head in focus, with the eyes most important (as always). If you have a tripod, use it, pick a focal point on one of the eyes. To get the whole head in focus, we want a depth of field that covers in front of the brow to the eyes, and from the eyes to behind the ears at least (we’re not going to be that worried about the back of the head, which we can’t see, being out of focus, or our plain background going a little blurred to hide defects). With the eyes about 1.25m from a 50mm lens, the near and far limits are 1.17m and 1.35m respectively. f/5.6 would give 1.19m to 1.32m; and that’s about as wide as we dare go, while keeping within the bounds of acceptability for the identity authority.
  • Set your camera in aperture priority mode (assuming you aren’t comfortable with manual metering), and half press to get an idea of shutter speed. If it’s anything slower than 1/60th of a second, then you’ll need a tripod, and the subject is going to have to make an effort to stay still. If you’re struggling, remember a click up to ISO 200 will help (if you’ve got a really expensive camera (why are you reading this?), then you can probably get as high as ISO 800 without difficulty.
  • You will probably want to slightly overexpose to get a brighter picture, so either manually meter to do so, or set your exposure compensation to +1 for white people, or +2 (for black people).
  • Take loads of photos; optimising each time. Be on the look out for dark backgrounds, shadows on the face, underexposure. You’ll be surprised how much the LCD on the back of a camera tricks you into thinking pictures are brighter than they really are.

Phew. A lot of work for a simple head shot isn’t it? The advantage is that this image is now yours forever. Now comes the post processing. Let’s think about what we want though. There is no point us sending the photograph we have taken directly to a print lab. We require photos that are a particular physical size, not this photo on a standard lab size.

Let’s talk aspect ratios. Print labs print at standard sizes. Our picture is smaller than the standard size. Further, those standard sizes have aspect ratios that are different from the aspect ratio of our desired output. Here’s some examples:

W H Ratio
45mm : 35mm = 9:7
6“ : 4“ = 3:2
6“ : 4.5“ = 4:3
7.5“ : 5“ = 3:2
9“ : 6“ = 3:2
8“ : 6“ = 4:3

We could simply shrink our image to an appropriate size, then put borders around it and print one small photo on one large piece of paper. That’s pretty wasteful though. We can definitely get more than one head on a single print. Let’s also remember that we can have the head portrait or landscape on the larger print (which we’ll treat as always being held landscape). Remembering that we only want complete heads (so we round down all divisions):

6" * 25.4 mm per inch / 45mm = 3
4" * 25.4 mm per inch / 35mm = 2
6" * 25.4 mm per inch / 35mm = 4
4" * 25.4 mm per inch / 45mm = 2

So for a 6“x4” print, we can get 6 heads if we arrange them landscape (on our landscape print), or 8 heads if we arrange them portrait (on our landscape print). Here’s the same calculations for the other typical print sizes:

Print Landscape Portrait
6“x4” 3 x 2 heads 4 x 2 heads
6“x4.5” 3 x 3 heads 4 x 2 heads
7.5“x5” 4 x 3 heads 5 x 2 heads
8“x6” 4 x 4 heads 6 x 3 heads
9“x6” 5 x 4 heads 6 x 3 heads
8“x8” 4 x 5 heads 5 x 4 heads
12“x5” 6 x 3 heads 8 x 2 heads

So, we’ve now got the maximum head count possible for each of the standard print sizes (note the interesting result that the massive 12“x5” print only gets 18 heads, while 9“x6” gets the most at 20 heads). Let’s find out the optimum size print. I’ll use low quantity prices from photobox, and calculate the pence per head using the above numbers:

Print size Price Cost per head
6“x4” 11p 1.375 pph
6“x4.5” 11p 1.222 pph
7.5“x5” 20p 1.667 pph
8“x6” 44p 2.2 pph
9“x6” 44p 2.75 pph
8“x8” £1.39 6.95 pph
12“x5” £1.69 9.389 pph
Passport photo service (8 heads) £1.99 24.88 pph

There is no economy of scale here, if you really wanted twenty heads it is cheaper to buy three 6“x4.5” prints (27 heads for 33p) than a single 9“x6” print (20 heads for 44p).

This result allows us to proceed using a single print size (however, I’m going to cover two sizes for a reason that will be apparent later).

Prep:

First let’s do a little maths.

  • Assume that our print lab prints at 300dpi.
  • There are 25.4mm per inch.
  • [mm] x [dpi] / [mm per inch] = [dots]
  • 45 mm x 300 dpi / 25.4 mm per inch = 531 dots (rounded down)
  • 35 mm x 300 dpi / 25.4 mm per inch = 413 dots (rounded down)

Therefore, we will be making 531 x 413 pixel images printed at 300dpi to make 45mm x 35mm physical printouts. There is no point having them any higher resolution than this (other than for you own satisfaction), because no standard print lab has equipment that prints at a higher resolution (and besides 300dpi is more than enough for an ID photo).

  • Open up your favourite photo in GIMP (or Photoshop if you like throwing money away).
  • Use the crop tool, set to a fixed aspect ratio of 9:7 and crop as large as you can to the right aspect ratio. This allows you to centre the head on the canvas.
  • Use the crop tool, set to a fixed aspect ratio of 9:7 to match the Passport service guidelines: eyes approximately centre and head vertically filling between 65% and 75% of the canvas.
  • Save this image as your high-resolution source.
  • Resize this image to 531 x 413 pixels. This is 45mm x 35mm at 300dpi.
  • I suggest now adding a few pixels onto this so that we end up with a natural margin between photos. This would be done with the resize canvas tool, and simply change it to 535 x 417 pixels and offset it to the bottom right to put the padding completely on the left and top. Note that the actual portrait is still 531 x 413, and so still 45mm x 35mm – there is simply an additional in the image. You’ll have to follow this with a layer-to-image-size operation.
  • Save this resized image in a separate file for assembling the prints.

For a 6“x4”:

  • We already know that the optimum is to arrange eight heads, portrait on a landscape print in a 4×2 grid.
  • 6“x4” @ 300dpi is 1800×1200 pixels
  • Load your resized single head image. Ensure it is shown portrait.
  • Use the tile function (Filters->Map->Tile in the GIMP) to create a 4×2 array of heads.
  • Use the resize canvas (not resize image, we don’t want to scale the image) function to make the image 1800×1200 pixels. The same function will provide a button to centre the old sized image on the new sized canvas – use it.
  • If you wish, use the text tool to write “45mm x 35mm on a 6”x4" print @ 300dpi" somewhere in the white border.
  • Save this file.

For a 6“x4.5”:

  • We already know that the optimum is to arrange nine heads, portrait on a landscape print in a 3×3 grid.
  • 6“x4.5” @ 300dpi is 1800×1350 pixels
  • Load your resized single head image. Ensure it is shown landscape.
  • Use the tile function (Filters->Map->Tile in the GIMP) to create a 3×3 array of heads.
  • Use the resize canvas (not resize image, we don’t want to scale the image) function to make the image 1800×1350 pixels. The same function will provide a button to centre the old sized image on the new sized canvas – use it.
  • If you wish, use the text tool to write “45mm x 35mm on a 6”x4.5" print @ 300dpi" somewhere in the white border.
  • Save this file.

(If you’re really keen, you can follow the above procedure to make images for whatever print sizes you want, the only difference is the tiling and the final image dimensions.)

Don’t worry about us having targeted 300dpi; printers automatically resize to match whatever dpi they are printing at. All we have done is ensure that there is enough resolution available in our source image to print at the industry standard: 300dpi. If your printer uses 290dpi, they’ll take care of it.

Now we have two image files that are the correct aspect ratio for two sizes of print. You could, if you wished, include one of these (probably the 6“x4.5”, to get the maximum number of heads for your money) in your next print order from a photolab. That will be the cheapest way of getting what you want – be careful to specify the right print size though, if you don’t you will not get 45mmx35mm photos.

However, if all you want is passport photos and you want them fast; the postal charges will completely swamp the price of the single print (for example: photobox want £1.49 to send a single 11p print). It’s still cheaper than a photobooth, but there is a better way: supermarkets and high-street photolabs.

Most supermarkets, and many high-street photolabs, have these little kiosk machines, that let you stick a USB pen drive into them to get a near-instantaneous copy of a photo. The problem is they are usually fixed size, and there is no way to know in advance whether that fixed size is 6“x4” or 6“x4.5”. You don’t care though, as you have both available. I went to ASDA and used a 6“x4” printer for 35p; and had my photos in seconds (I was amazed at how quickly these things work).

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