The starting point: A historical black and white photo print from 1944. It is tiny, just about 6 x 6 cm (2.4″ x 2.4″), and it is slightly tilted as the photo had been glued into the photo album, not exactly upright. The scan has been made following the process described below. The optical impression on my calibrated screen is very close to the original print in the album.
Okay, the basement is full of photo albums containing unique family photos and sometimes even historical moments, and you notice that some of the photos – especially those from the 1950s and before – already show serious damages. You want to save them from further deterioration, but you don’t know where to start. You think – “Gee, I should scan all these wonderful photos to preserve those memories for future generations.” Then you realize that you need to scan and restore hundreds and thousands of images, and you probably let out a big sigh and conclude: “Well, not now!” The album goes back on the shelve until you go through this little routine again the next time. Unfortunately, this will just destroy your photos further!
I guess that most of you know this cycle.
Truth is, at some point you just have to scan the images, or they will be lost forever. Now, if you are serious about the task, this little article will help you preserving those precious images without getting lost in the details (and spending too much time). Yes, it can be done!
:: Scanning the images
The basic idea is to capture the photos with as much image information as possible while avoiding any interpretation of the images at the time of scanning. In other words: You want to capture the images “as they are” without altering the optical impression. Remember, you want to archive and preserve the images. But don’t worry! You will have plenty of opportunities to interpret/improve the images later. But to do this, you will need decent scans.
1. You will need a good, modern flatbed scanner with an optical resolution of 1200 dpi or higher. The scanner should support 48 bit mode (i.e. 16 bits per color channel) and be able to save the images using the TIFF format. I use an EPSON PERFECTION 4870 PHOTO for this task. (It is an older model, but it does the job perfectly.)
2. You should familiarize yourself with the scan software that comes with scanner. You will need to know how to use the professional mode to control exposure, color space and resolution.
3. Setup your scanner for TIFF (uncompressed), 48 bit depth, and 1200 dpi. This setup will create huge amounts of data, probably more than the original print carries. For example, a 4×6 print will be 4 x 1200 x 6 x 1200 = 34,560,000 pixels, or 34.5 Megapixels. But we have three colors, and each color has 2 Bytes of data for that pixel. The resulting file is thus 34,560,000 x 3 x 2 = 207,360,000 Bytes, or roughly 197.8 MB. Ouch. Not even the original negative might have had that amount of information! But hard disks are cheap these days, so it may be a good investment to buy a 1 TB disk that can store 5,000 high resolution scans at 200 MB each.
3a. Whether you really scan at 1200 dpi or use 800 dpi or 600 dpi will depend on your needs, and the quality of the originals. If you just want to achieve the same size of the original, a 300 dpi scan is fully sufficient. As we want to preserve as much information as possible, we scan at a higher resolution. It is essential that you scan at 48 bits color depth! This will provide 2^16 = 65,536 shades per color (instead of just 2^8 = 256), so the photo software will have 256 times more data to work with. And this, dear reader, will make the difference! Faded colors can be restored without losing details in the shades.
3b. If your scanner supports Adobe RGB, you will want to use it instead of sRGB. This may help you getting as many shades as possible from the scan.
4. Before you start bulk scanning the photos, it is important to find out the darkest and brightest points. Then do each scan with the same settings. To find these, you will want to use a color target (as sold by Hartblei for little money). Basically such a target contains a really dark patch (“O”), a really bright patch (“1″), and a neutral gray patch (“Balance”), plus many more patches to control the quality. For our task, only the basic patches are important. Now do a scan of the target with the automatic controls switched off. Open the resulting image in Photoshop. Check the histogram for the darkest point (“O” patch). It should be close to zero (the left side of the histogram). If it is not there yet, you need to reduce the exposure in the scan software. Do likewise for the brightest spot in the image (“1″ patch). It should be at the right side of the histogram. Repeat this until you are satisfied with the result, i.e. the histogram spreads nicely from left to right. Then write down the values to achieve this (for future use). When you are able to create a decent scan of the target, you are ready for the scanning of the final images. Keep the last original scan of the color target. You will need it later when we process the images in Lightroom.
Color target, available from hartblei.eu
5. Start scanning your images with the settings laid out above. The only important thing to remember is to use always the same exposure settings, and to scan at 48 bits. The resolution depends on what you want to achieve. (I think that more than 1200 dpi is not useful for historic photo prints.)
6. At the end of this process, you’ll have thousands of high-resolution images on your hard disk. These will probably look like the shot above.
:: Making basic corrections
Once all the scans have been done, we make basic corrections: color, exposure, sharpness, cropping, tilting. The goal is to come up with digital images that look like the original photos in your album.
1. In order to batch process the huge amounts of images, you will need a batch processing software that is capable of handling the images you scanned before, i.e. the software must support large TIFF files with 48 bits color depth. I use Adobe Lightroom 4.1, but there are alternatives. Lightroom handles 48 bit TIFF files in Adobe RGB without problems.
2. Import all image files and the single scan of the color target into Lightroom.
3. Select the color target, and switch to Develop mode. First, you should adjust the color balance using the Pipette tool. Point the pipette to the “Balance” field to get rid of any color stains. Then adjust Contrast, Highlights, Whites, and Blacks, so that the pixels of the color target are not yet clipping. (“Clipping” happens when some pixels in the image are too bright or too dark.) Again, the histogram should spread from far left to far right. At this time you can also adjust the sharpness by zooming on the “focus” patch and adjust the Sharpening of the image.
4. Once you have done this, select all images of your import (Ctrl-A) and then Sync… all the settings (that you used to correct the color target) to all your scans. After this, all images should look like the originals in the album.
5. Now all you have to do is to manually turn and crop each image. Again, I recommend to not interpret the image yet by cropping away parts of the image. Rather try to preserve as much of the original image (but remove the borders surrounding the image).
6. Once you are done, you have digital copies of your historical photos on your system. You can now export these images to your hard disk as sRGB JPEGs at any size you want (e.g. 1200 pixel width with 300 dpi). This would be fine for ordering small prints, showing around on a laptop computer, or for uploading to Facebook. As Lightroom is non-destructive, you can always export larger images when needed.
:: Finetuning the images
It is quite likely that you are not satisfied with the results so far. After all, you scanned damaged images, and now you have an image file that looks exactly like that flawed original. But you wanted improved images, right? Right.
7. Now you can manually fine tune each image in Lightroom as your time permits. All the image data is available in high resolution. The original scan will never be altered by Lightroom, so you can do as much fiddling and experimenting as you desire. :-) If you do not like a result, you can always start over again. Here is what I do. The values in brackets are the values used for the image above. Please note that the values will vary for each individual image.
8. Set the image to B&W.
9. Increase Contrast so that the histogram spreads nicely between the darkest and brightest spots. (+75)
9a. If needed, reduce the Blacks. (-50)
9b. If needed, increase the Whites and the Highlights. (+20, +10)
9c. If needed, increase the Shadows. (+30)
9d. Check again, that the image does not “clip” on either side of the histogram. (Lightroom indicates “clipping” by little triangles in the histogram.)
10. Adjust the Sharpening (+60)
11. Create a virtual copy of the image and open the copy in Photoshop. Now use the Remove spots and scratches filter (from Filter > Noise filters menu). For this image, a “radius” of 1 pixel and a “threshold” of 25 was perfect. You may need to fiddle around a bit to find the right values.
12. Finally, export the image to your hard disk as sRGB JPEG:
The restored historical photo. This is probably the original look when it came back from the lab in 1944. The image has been cropped and tilted. Contrast has been recovered. Dust and scratches have been removed. It has been sharpened, and it is true black and white again (despite being a sRGB color file).