In certain cases the number of bits per color channel may be increased to 12 or even 16 in the process of scanning. As a result, we’ll get a very detailed image a lot larger in volume. But you should take into account that it is possible to edit such a file with a greater color depth in the professional graphics editors, e.g. Adobe Photoshop, and it requires good skills. Besides, from my personal experience, I can say that such an increase in the number of bits is not always justified in practice.
To make the account complete, we’ll touch upon another characteristic feature of the scanner. It is a Dynamic Range or a Density Range. The Dynamic Range is the difference between the lightest (Dmin) and the darkest (Dmax) parts of the source photo the scanner is able to process. The higher the Dynamic Range is, the more there are gradations of brightness and hence, the softer the changes in the adjacent color shades of the image. I can’t but mention that very often this feature is not indicated by the manufacturers in specifications of non-professional scanners.
Now we can perform the preliminary scanning ’Preview image’ of the image. This procedure is intended for the preview of the digital version of the original with low resolution. After the preliminary scanning ’Preview’ if the size of the original photo is smaller than the working area of the scanner (e.g. we are scanning a photo 4 x 6 inches in size), we only need to single out the area of scanning along the frames of the original with the enlarging easel, the Grop tool. The enlarging easel is a number of dotted ’running’ lines making up a rectangle where the image is to be enclosed. Some makes of scanners are equipped with a measuring element to determine the size of the original; it enables to determine the area of image capture automatically.
When scanning, on no account use all kinds of software filters such as increase of definition, Auto Contrast & Color Correction, Auto Exposure, Sharpness etc. you should also avoid correcting the image with the Brightness/Contrast operation. All these will lead to the irreversible loss of information. As has been said, our aim is to get a digital file containing the most complete and undistorted data of the source photo.
You shouldn’t be confused that after the final scanning the obtained digital photo may look somewhat faded. It is because such a raw file will have a lot of necessary data of the original photo so as, when editing it, to get the most similar to the original digital replica and then a printed one.
Having performed the scanning, the file should be saved. We are going to talk through the two most widespread and the most preferable files out of the variety of graphics files – TIFF (Tagget Image File Format) and JPEG (Joint Photographic Experts Group).
TIFF is a widely used format of bitmapped (raster-scan) graphics. Image preservation in this format, to my mind, is the optimum solution. First of all, this format is absolutely safe for the quality of your file; moreover, in order to reduce the volume of the image you can use LZW-compression, which doesn’t result in the loss of qualitative characteristics of the file.