I needed passport size photographs, so I headed down to my local photo center to get them taken. However, they did not do a very good job of it. They used polaroid cameras, which essentially gave them only one shot at getting it right, and they did not. I was determined to see if I could do a better job.
In this tutorial, I will try and explain the process involved in importing the image in GIMP and output and image that can be photo printed.
Tip: If you do decide to take your own pictures, make sure your final image is in accordance with the guidelines link present above. I had most trouble with control over lighting issues, and ended up taking pictures in my bathtub, which is where I could control the lighting and background shadows the best.
The composition page states the dimensions of the required pictures.
We will need to ensure that we meet the dimensions specified here.
So, we have ourselves a good photograph. This will be sufficient to learn the process of image editing.
Firstly, we need to measure the distance from the top of the hair to the bottom of the chin. We do that by using the measure tool in the GIMP. Use the option, Show Info Window to conviniently display the dimensions.
Let us use the measure tool to measure the distance from the top of the head to the chin.
Note down the value displayed in the info windows. In this case, it turned out to be 864 pixels. This will be different with your image.
This distance, when printed on the actual photograph should be between 1 - 1.375. Let us assume that when printed, this image will be bang in the middle, 1.1875 inches. So, we shall determine the DPI by dividing the number of pixels obtained in the previous step, with this value.
Required DPI = (Size of the head in Pixels)/(Size of Head in Inches) = 864/1.1875 = 728 (approx)
The final photo will need to be 2"x2", so the size of the total image in pixels will need to be (Required DPIx2) x (Required DPI x 2) = 1456 x 1456. We will need to crop the our original image using these dimensions.
Pick the Rectangular Select Tool, and set Enable the Fixed checkbox option. Select the dropdown Size and set it to the size of the image obtained in the previous step. In this case, it is 1456x1456. Also, select the drop down which says No Guides and change the option to center lines. This allows use to center the image easily.
Centered the rectangular box on the nose. This should ensure that we meet our second requirement of the eye-height from the bottom of the photograph (this should be our rectangular box). Quickly check the height of the eyes from the bottom of your box (Pixel length/DPI = actual length). Once you are satisfied, crop the image by picking Image->Crop to Selection from the menu bar.
Create a new image from the GIMP program. Select File->New from the menu bar, then set the image size to 4x6 inches. Click Advanced Options to set the X and Y resolution to 728 pixels/in (required DPI, calculted previously). You may also want to set the Fill With option to White. This should open up a new window, with a blank image.
Go to the previous window, with the cropped image. Choose Select->All to select the image, and Edit->Copy to copy the entire image. It is also possible to use the Ctrl + A shortcut to select all, and Ctrl + C option to copy.
Go the the window with the new blank image, and paste the image using Edit->Paste or the Ctrl+V shortcut option. Move this image to the top. Repeat the paste process, and move the image to the bottom.
Save the image by choosing File->Save. It is recommended to use the GIMP image format for saving it initially. Then do a File->Save as to save the image in the jpeg/png format, which will be sent to the photo printer.
If you have a photo printer, you can print the image obtained in the last step. If you donot, you can print it using your local retailer having photoprint services. There are several around, I used walmart.com to print my images. I was able to upload the images using their website, and picking up my prints in an hour.
After the photos have been printed, use a ruler to make sure the dimensions are correct. If they are, you are finished with this process! Have a safe trip!
This page was last edited: Jan 1 2008