Post-scanning
Adjustments
Photoshop
is used for a number of post-scanning tasks, such as cropping, rotating,
correcting color and removing dust, scratches and possible moiré patterns not dealt
with in Silverfast. Most of these tasks can be
accomplished through tools on the toolbar and filters. Color adjustments in
Photoshop, however, can cause degradation of the image data. The use of
Adjustment Layers can prevent this. Don’t go crazy trying to remove every speck
of dust or extensive scratching. It may be impossible and most of it won’t be
visible in the derivative JPG. Consider that you need only create the illusion that the scratch isn’t there,
not remove it completely.
PLEASE take the book off the platen or remove the slide from the scanner and look at it carefully before making adjustments. A common mistake in scanning is to save an image that is flipped or upside-down. If there is text in the image it should be readable!
A.
Rotating,
straightening and cropping
1. Rotating
a.
Go to Image > Rotate
Canvas and choose the desired rotation
i. Occasionally you may
need to flip an image horizontally or vertically. This is usually because the
slide was mounted incorrectly, or you inserted the slide into the scanner
wrong. A good clue that correction is needed is if any text in the picture is
backwards or upside down.
2. Straightening
a. Crop tool
i. Click the Crop tool
on the toolbar
ii. Draw a marquee around
the image
iii. Move your cursor
outside the crop box until you see a double-headed, curved arrow
iv. Click and drag to
rotate the box
v. Double-click inside
the box to complete the crop
b. Measure tool
i. Click on the Measure
tool on the toolbar.
a. Measure is hidden
behind the Eyedropper tool. Click and hold the Eyedropper for a menu of tools
behind it, then click on Measure
ii. Find a line on the image (vertical or horizontal)
that you think should be straight
iii. Click and hold on one
end of your line and drag the curser to the other end of your line and release
the mouse button. A line should remain on the image
iv. Go to Image >
Rotate Canvas > Arbitrary… The tool has automatically measured to rotation
needed to make your line straight
v. Click Ok
3. Cropping
a. Click the Crop tool
on the toolbar
b. Draw a marquee around
the image
1. Use the “handles”
around the crop box to adjust it
2. Try not to crop anything
important. If you need to leave a little bit of the black or white frame around
the image in spots, that’s fine. It just means that the page of the book or
object wasn’t exactly parallel with the lens of the camera when the picture was
taken. You may elect to eliminate these bits of frame using the Clone Stamp
tool (see below)
c. Double-click inside
to box to complete the crop
1. Click on View >
Actual Pixels (or Ctrl/Apple and “-“ or “+” to zoom in
or out) to see the image at its full dimensions. Start and one corner of the
image and scroll up and down and left and right to be sure you have surveyed
the entire image for correction. Return to Fit on Screen when you are done to
check if you missed an area
2. Clone Stamp tool
a. Click the Clone Stamp
tool on the toolbar
i. Adjustment to the
Clone Stamp can be made using the toolbar that appears just below the Photoshop
menu bar when you select the Clone Stamp. Mostly you will adjust the size of
the brush and the hardness. The harder the brush the less blending happens
around the edges of the brush area
b. Choose a clean area
on the image close in tonal value to the area you wish to correct
c. Hold the Alt key down
(the cursor becomes a target) and click to copy
d. Move to the damaged area
and click to paste
i. Note that when you
click to paste a “+” appears in the clean area you chose to copy. The relative
position of the copy area stays constant to the brush, i.e. if the clean area
is 20 pixels away at a 45 degree angle, no matter where you move on the image,
the next time you click to paste you will be pasting the area 20 pixels away at
a 45 degree angle. To resample you must Alt+Click
again
ii. The Cone Stamp is
useful for small areas with great tonal/color variation, i.e. lines or edges. Use
the Spot Heal tool for larger areas with subtle tonal/color changes
3. Spot Heal tool
a. Click the Spot Heal
tool on the toolbar
i. Adjustment to the
Spot Heal tool can be made using the toolbar that appears just below the
Photoshop menu bar when you select the Spot Heal tool. Mostly you will adjust
the brush size and hardness. The harder the brush the less blending happens
around the edges of the brush area
b. Click on the area you
wish to correct
i. Essentially the Spot
Heal takes pixels from in and around the area of the brush and blends them all
together. This is useful for large areas with subtle gradations of color, like
the sky or flesh
1. Ideally all color
correction should be done in Silverfast before the
scan is actually performed, but occasionally you will need to make slight
corrections in Photoshop. If the corrections are drastic, you may want to
rescan instead
2. Adjustment Layers
a. Go to Layer > New
Adjustment Layer and choose the kind of correction you wish to perform (these
are the same as the choices under Image > Adjustments)
b. Click Ok to accept
the automatic naming of the Layer
c. Adjust the image
using the dialog box
d. Click Ok to save
e. Create another
Adjustment Layer if necessary
f. When all adjustments
are done, click on Layer > Flatten Image to merge all Layers
i. If you fail to
flatten the image, during the save dialog you will see a compression option
available that is not there if the image is flat, and you may also get a
warning dialog about the large size of files with Layers saved. Cancel the save
and flatten the image before proceeding
1. Moire patterns are created
by the scanner reading a commercially printed page and picking up the dot
pattern of the printing process. For printed material, the Gold descreen setting in Silverfast
will take care of most or all of the problem. Moire patterns from copystand
photography should be handled in Photoshop using one of the following methods
2. Remember to look at
the image in various sizes (View > Actual Pixels and Ctrl/Apple – and Crtl/Apple +) to determine the severity of the moiré.
Generally speaking, if the moiré isn’t bad when the image fills the screen or
slightly smaller, it will not translate to the derived JPG, which is ideal
3. Despeckle filter
a. Click Filter >
Noise > Despeckle
i. Despeckle is an automatic
filter and is a rather blunt instrument. If Despeckle
is not effective or overcorrects go to Edit > Undo Despeckle
and try the method below
4. Gaussian Blur + Unsharp Mask
a. Blur only until you
just begin to not see the moiré. Sharpen up just below the threshold of the
moiré returning
b. Click on Filter >
Blur > Gaussain Blur
c. Adjust the blur in
the dialog box. As a general rule, the adjustment should be between 0.5 and 1.0
or the image integrity is in peril
d. Click on Filter > Sharpen
> Unsharp Mask
1. Adjust the sharpness
in the dialog box. As a general rule, don’t get too far from a threshold of 0,
a radius of 1.0 and an amount between 50 and 80%
5. Sharpen
a. Descreening can cause a
significant loss of sharpness in an image. If you used a Silverfast
preset that contained a descreening filter (Silver
color, Gold descreen) you may need to sharpen the
image slightly in Photoshop. Be careful that you do not reintroduce a moiré pattern
back into the image
b. Click on the
Background in the Layers window (Windows > Layers)
c. Click on Layer >
Duplicate Layer
d. Click Ok to accept
the automatic naming of the layer
e. Filter > Sharpen
or Sharpen Edges
i. If the filter applies
too much sharpening to the image, go to Edit > Fade Sharpen (Edges) and
lower the opacity
f. When all adjustment
is done, click on Layer > Flatten Image to merge all Layers
i. If you fail to
flatten the image, during the save dialog you will see a compression option
available that is not there if the image is flat, and you may also get a
warning dialog about the large size of files with Layers saved. Cancel the save
and flatten the image before proceeding
1. Occasionally you will
have an image that is spread over two or more pages in a book or is too large
for the flatbed scanner (and the Staff has opted not to use Digital copystand photography to scan it.) In these cases you can
scan parts of the image, and then merge them in Photoshop.
2. Scan all parts of the
image as you would individual images, allowing generous borders around them.
a. You will want to scan
the largest part first, with a generous border, to make sure your frame can
accommodate the smaller parts in subsequent scans
3. DO NOT RESIZE THE
MARQUEE IN SILVERFAST!!! You may move the marquee to accommodate the position
of the next part when you Prescan,
but if you resize it, the two (or more) parts will not match up when you try to
stitch them together.
4. Keep the scans of the
parts open in Photoshop without saving them until all scanning is complete
5. Straighten and rotate
each image as needed
6. Choose one end of the
original picture to act as the background upon which you will paste the other
parts
7. Select one of the
non-background parts and go to Image > Canvas Size
8. Write down the
dimensions of the canvas in pixels, then cancel the action
9. Repeat for any other
parts
10. Select the background
part and go to Image > Canvas Size and determine the dimensions in pixels. Keep the dialog open
b. Enter the combined
pixels for the width (or height) in the width (or height) box under New Size
c. In the Anchor diagram
choose which side you want the background on and click the arrow on that side
to move the white box to where you want the background to be located. Click Ok
to close the dialog. Extra white space will appear at one end of the background
image
11. Select one of the
parts
a. Use the Marquee tool on the toolbar to draw a
box around the entire image, then cut and paste it into the background OR
b. Click the Move tool
on the toolbar and drag the part image onto the background image
12. Use the Move tool on
the toolbar to position the part over the background and line it up as closely
as possible
a. If you are having
trouble, you can use Layer > Layer Style > Blending Options and adjust
the General Blending Opacity down to make the part translucent, so you can see
the background underneath it. Reset the Opacity to 100% when you are done
13. Repeat to add all
parts to the background
14. Go to Layer >
Flatten image to combine all parts into the background
15. Use the Clone Stamp
or Spot Heal tools to blend any seams, if possible
F.
Saving
images and Administrative tasks
1. Go to File > Save
as…
2. Enter the Accession
number from the Order Form for the image
3. Save it as a TIF
file, with extension
a. In the dialog that
appears after you click Save make sure of the following:
i. Image Compression:
None
ii. Pixel Order:
Interleaved
iii. Byte Order: IBMPC
iv.
Save Image Pyramid:
Unchecked
v. Layer Compression:
Grayed out
a. If the Image
Compression is available, you did not flatten the image after creating Layers.
Cancel the Save As… and go to Layer > Flatten Image, then try saving again
4.
Place an “X” next to
the Accession number on the Order Form to
indicate that the image has been scanned
5.
At the end of your shift,
write your initials and the date in the margin of the Order
Form next to the last image you scanned
6.
When all scanning for
an order is done, fill out the Order
Tracking Sheet with the appropriate information
Continue
to Attaching Metadata