We want to get an image directly from the scanner, which comes as close as possible to the final print. We want to avoid performing lots of digital adjustments in our image editing tool, like Photoshop. The image below illustrates the "analog" quality of an image that has been properly exposed, developed by inspection, and scanned in a simple, straightforward manner.

Scan of 5x7 negative. Ilford FP4+ film, developed in Pyrocat HD, February 2010

Don't tell the Photoshop sales and training community, but the more digital "corrections" we make to an image, the more artificial it tends to get. If you admire a more manufactured and glamorous look, you might want to skip over this article. Our goal here, is to reveal the natural beauty you already captured on film, with minimal distortion.

The Sample Image

Here is a negative, made on 5x7 inch Ilford FP4+ film, and developed in Pyrocat HD. The subject is a pair of pink roses, in overcast light. It's not the greatest photo in the world, but it makes a good demonstration, because the tones are fairly close and subdued. If a scan is good, the image should convey subtle nuances of shading. Or as my mentor Fred Picker used to say... "It should feel like Light". In a picture like this, a faithful and delicate rendering of the subject is the photograph.

The taking lens for this photo, was of vintage design, chosen for its "gentle but sharp" focus, and soft rendition of background blur: an old 180mm Carl Zeiss Jena Tessar. The actual negative is rather soft in appearance: as the histogram shows, the tonal scale occupies no more than 40% of the scanner range.

Preview - What Is the Scanner Thinking ?

The default Preview settings have made the image appear quite harsh: the Input high values have been clipped, and appear pure white - like chalk. Meanwhile, the overall Output has been constrained on both ends of the tonal scale: instead of 0-255, our image contains only 10-200. Now let's see how to make things look much nicer.

Correct the Histogram Before Scanning

We have corrected the default Output settings. They now go from 0 to 255. We have adjusted the Input settings so that the dark values on the left side, are just dark enough to render the black film edge as black - but no darker. The right-side setting is light enough to show the high values naturally, without any clipping or unnatural loss of texture. (These roses were pink. We don't want them to look bleached out). Finally, we adjust the middle setting (Gamma) to taste.

Now We're Ready to Scan

The Preview feature has let us adjust the scanning settings, so our scan will get us as close as possible to a perfect rendition of this negative.

We set the scanner to give us a 16-bit greyscale TIFF file. Unlike JPEG (which is "lossy"), the TIFF format results in no loss of visual information. (TIFF stands for Tagged Indexed File Format. JPEG stands for Joint Photographic Experts Group.) For color negatives and slides, use 16-bit color - also known as 48-bit color, because each of the Red, Green, and Blue channels, get 16 bits.

After the Scan

In our editing tool (Photoshop) the image looks pleasing and natural. To tone the image with a warm but subtle color, we have applied a non-destructive Color Fill Layer according to taste.

Against a white background, the image feels different than when against the black background of the scanner software. Depending on our choice of matting and frame, we may decide to adjust the tones of this photograph a bit further.

Finally, we save the file in the Photoshop PSD format, which uses a lossless compression algorithm. The file is smaller than the original TIFF, but no quality is lost. To post this image on the internet, we can always make a JPG file later (8-bit only), but our working file is in PSD format, at full 16-bit resolution. We can also keep the original TIFF if we like.

Summary

We have managed to get an image that feels like soft natural light, right out of the scanner. Very few further adjustments will be needed in Photoshop - and that's for the best - since every digital adjustment distorts the image in one way or another - even the so-called "non-destructive" adjustments.

To preserve the natural "Analog" quality of the original negative, we scanned the image in 16-bit monochrome, and saved it in a lossless file format. The 16-bit format gives us 65,536 shades of grey to play with, to reduce any banding, clipping, or other digital artifacts which may arise if we make further adjustments.

Another Summary

I take the dubious position that it's best to get things right, as early as possible, rather than "down-stream" in the process.

In other words, skip subjects that don't look beautiful. That's 99% of the issue. For the remaining 1%, expose the photo as well as possible, and develop accordingly, adjusting the negative with expansion and contraction. Development by inspection with an Infra Red viewing device takes this even further, and makes it easy.

In the scanning phase, you have your last big chance to get things perfect, if they aren't already. This is where you make the transition to digital, and if you want to keep things looking as analog as possible, it should be your last major tonal correction.

After that, you can use a tool like Photoshop to make small corrections, but it's best to minimize them, or your images will look like they come from a slick commercial magazine.

Which Scanning Resolution ?

You choose the scanning resolution, depending on how much you plan to enlarge the original.

To get good quality, you need to print at 300 dpi (dots per inch) minimum. At that level, people can stick their nose close to the print and not see any dots, and the image will appear critically sharp. However, people can see more that 300 dots. Laser printers work at 600 dots, because letters appear ragged at 300.

If you scan at 600 spi (samples per inch), you can make a print at the same size as the original. If you scan at 1200 spi, you can make a print which is twice the size of the original. If you scan at 1800 spi, you can make a print which is 3 times the size... etc.

Let's say you have a medium format negative which after cropping, is 2x2 inches. You want to make a 10x10 inch print. That means you plan to enlarge by a factor of 5. In that case, you need to scan at 600 x 5, or 3000 spi.

Let's say you have a 4x5 slide. You want to make a 12x15 inch print. That means you plan to enlarge by a factor of 3. In that case, you need to scan at 600 x 3, or 1800 spi.

Let's say you have an 8x10 negative. You want to make an 8x10 inch print. That means you don't plan to enlarge at all. In that case, you can scan at 600 x 1, or 600 spi.

Epson Printers

While Canon and HP printers work with multiples of 300 dpi, Epson printers work best in multiples of 360 dpi. So if you plan to enlarge 5 times and print at 360 dpi, you will want to scan at 5 x 360, or 1800 spi. If you plan to send 720 dpi to the printer, then you need to scan 5 x 720 or 3600 spi.

How Much Can We Really See ?

The limiting factor may be the paper. According to this article, the eye can see at least 600 dpi. Modern laser printers no longer print at 300 pixels per inch, but 600 - because people can see the difference: letters appear smoother. Inkjet printers can go up to 1440 or higher. So if you want to delight the eye, print at 600 or higher. On an Epson, try 720 and 1440 with your favorite paper. If you can't see a difference, it's probably because the paper is too ragged.

Best Practices

For your serious work, it's probably a good idea to scan at a higher resolution than you need. You can always down-size the image to print at whatever size you like. The only problem with this approach, is that you end up with large files, which are expensive to store. Nowadays, you can purchase an affordable external hard-drive. It's safer than leaving them on the computer itself, which is more subject to failure and accidental deletions in the long-run.

RBG files are 3 X the size of Grayscale images, so if you want to save room on your hard drive, don't save your monochrome images in RGB. Just save them in 16-bit B&W. When it's time to print, you can always convert to RBG and add a Color Fill layer for toning purposes. You can save the toning layer in your Guide File image (see below).

Be sure to read You Don't Need a Super Computer