Scanning Artwork
If you need to reproduce images of artwork for display on a web site, or printing, scanning produces far superior results to photographing. Flatbed scanners provide even illumination with no shadows at the edges (often observed in photographs). Similarly, there is no fall off in sharpness at the edges, nor distortion of verticals and horizontals, both of which are frequently created by camera lenses.
Scanning is quick and easy to do, provided your artwork fits your scanner.
Most home use scanners are A4 size, but artwork can often be larger than A4. The aim of this article is to provide some tips on scanning A3, or A2 artwork using an A4 scanner.
The principle of scanning larger artwork is very simple: you scan in sections, and "stitch" these together in PhotoShop. However, there are a few other steps that need to be taken to produce a seamless image.
1. Before you start to scan, make sure that the paper or board your artwork is made on has four perfectly straight and square edges (this step should only be necessary if the paper has been cut to size, and lost its manufactured uniformity).
2. When placing the artwork on the scanner bed, take great care to line-up the paper parallel with the edge of the scanner bed. If it is a tiny bit out of alignment, the separate scans will not line up perfectly, and rotating the image in PhotoShop will seldom correct alignment discrepancies easily and absolutely.
3. Because the image being scanned is bigger than the scanner bed, it cannot lie perfectly flat (in contact with the glass) at its edges, so you will need to discard a few inches of the perimeter of the scan, which will effectively be "out of focus", and foreshortened.
4. You will also need a few inches of overlap between images. It is far easier to join images by overlapping them, rather than attempting to match-up the edges of scans (more about this in a moment).
Point 3 and 4 taken together mean that each segment scanned will be smaller, than A4, and the total number of scans you need to make must be planned accordingly. An A3 size image, for example, will normally require three scans (the left side, the right side, and the middle).
5. Be aware of tonal variations in your artwork. When sections are scanned, each will be exposed according to the requirements of the image (with most home scanners, the level of exposure is automatic). For example, say you are scanning a portrait of a woman with dark hair, and a light dress. The scan of top section of the image will receive stronger illumination than the bottom. This variation in the level of illumination will often manifest in the background colours: they will appear lighter in the top section against the dark hair, and relatively darker in the bottom section against the light dress. If you are scanning an artwork with such tonal variations, you may need to scan more sections, or section the image differently in order to even-out those exposure variations.
There are many different versions of PhotoShop, so I will assume that you have some knowledge of the software's features, and how to evoke them.
6. Briefly, open the first image, and crop away the edge that was not flat not the scanner bed (if you did not do this at the scanning stage). Adjust the canvas size to accommodate the entire assembled picture.
7. Open the second image (crop if necessary) and drag and drop it into the first. Nudge the second image until it correctly aligns to the first. There are a few things you can do to check alignment. Try holding a pencil point on the screen at some distinctive "check point" in the area of overlap between the two images, and switch one image in and out of view. You should see the "check point" move as you switch between image views if the two are incorrectly aligned.
8. Adjusting the transparency of the second image will enable you to see through it, and this can be a good supplementary method of checking alignments.
9. Always check alignment at several points along the join, since if your scans are out of parallel, images may not align throughout the length of their join. If you encounter this problem, go back to step 2, and re-scan.
10. When you have the images perfectly aligned, erase the edge of the image in the top layer. This helps to soften and mask the join, so that it becomes totally invisible. If your overlap is sufficient, you can selectively erase more or less of the top layer. For example, a join along the line of a dark tree trunk is a good place to make an invisible join.
11. Fine adjustments to the brightness, contrast, and colour balance can iron-out any exposure discrepancies evident at this stage. If you have planned your scan sections well, this step should not be necessary, or require only very minor tweaks.
12. Once you have two images joined, open the third image and repeat step 7 onwards.
13. When you have all of your scans joined, merge the layers into one. Now you can adjust the brightness, contrast, and colour balance of the whole image if it does not accurately match the original artwork (remember in step 11, the was merely to match the brightness, contrast, and colour balance of one image to another).
14. Finally, move to a high level of magnification and thoroughly inspect your image for imperfections (like dust or fibres on the scanner bed). The "healing brush" is a good tool for removing blemishes.
Portraits by John Burton
Scanning is quick and easy to do, provided your artwork fits your scanner.
Most home use scanners are A4 size, but artwork can often be larger than A4. The aim of this article is to provide some tips on scanning A3, or A2 artwork using an A4 scanner.
The principle of scanning larger artwork is very simple: you scan in sections, and "stitch" these together in PhotoShop. However, there are a few other steps that need to be taken to produce a seamless image.
1. Before you start to scan, make sure that the paper or board your artwork is made on has four perfectly straight and square edges (this step should only be necessary if the paper has been cut to size, and lost its manufactured uniformity).
2. When placing the artwork on the scanner bed, take great care to line-up the paper parallel with the edge of the scanner bed. If it is a tiny bit out of alignment, the separate scans will not line up perfectly, and rotating the image in PhotoShop will seldom correct alignment discrepancies easily and absolutely.
3. Because the image being scanned is bigger than the scanner bed, it cannot lie perfectly flat (in contact with the glass) at its edges, so you will need to discard a few inches of the perimeter of the scan, which will effectively be "out of focus", and foreshortened.
4. You will also need a few inches of overlap between images. It is far easier to join images by overlapping them, rather than attempting to match-up the edges of scans (more about this in a moment).
Point 3 and 4 taken together mean that each segment scanned will be smaller, than A4, and the total number of scans you need to make must be planned accordingly. An A3 size image, for example, will normally require three scans (the left side, the right side, and the middle).
5. Be aware of tonal variations in your artwork. When sections are scanned, each will be exposed according to the requirements of the image (with most home scanners, the level of exposure is automatic). For example, say you are scanning a portrait of a woman with dark hair, and a light dress. The scan of top section of the image will receive stronger illumination than the bottom. This variation in the level of illumination will often manifest in the background colours: they will appear lighter in the top section against the dark hair, and relatively darker in the bottom section against the light dress. If you are scanning an artwork with such tonal variations, you may need to scan more sections, or section the image differently in order to even-out those exposure variations.
There are many different versions of PhotoShop, so I will assume that you have some knowledge of the software's features, and how to evoke them.
6. Briefly, open the first image, and crop away the edge that was not flat not the scanner bed (if you did not do this at the scanning stage). Adjust the canvas size to accommodate the entire assembled picture.
7. Open the second image (crop if necessary) and drag and drop it into the first. Nudge the second image until it correctly aligns to the first. There are a few things you can do to check alignment. Try holding a pencil point on the screen at some distinctive "check point" in the area of overlap between the two images, and switch one image in and out of view. You should see the "check point" move as you switch between image views if the two are incorrectly aligned.
8. Adjusting the transparency of the second image will enable you to see through it, and this can be a good supplementary method of checking alignments.
9. Always check alignment at several points along the join, since if your scans are out of parallel, images may not align throughout the length of their join. If you encounter this problem, go back to step 2, and re-scan.
10. When you have the images perfectly aligned, erase the edge of the image in the top layer. This helps to soften and mask the join, so that it becomes totally invisible. If your overlap is sufficient, you can selectively erase more or less of the top layer. For example, a join along the line of a dark tree trunk is a good place to make an invisible join.
11. Fine adjustments to the brightness, contrast, and colour balance can iron-out any exposure discrepancies evident at this stage. If you have planned your scan sections well, this step should not be necessary, or require only very minor tweaks.
12. Once you have two images joined, open the third image and repeat step 7 onwards.
13. When you have all of your scans joined, merge the layers into one. Now you can adjust the brightness, contrast, and colour balance of the whole image if it does not accurately match the original artwork (remember in step 11, the was merely to match the brightness, contrast, and colour balance of one image to another).
14. Finally, move to a high level of magnification and thoroughly inspect your image for imperfections (like dust or fibres on the scanner bed). The "healing brush" is a good tool for removing blemishes.
Portraits by John Burton
Source...