Color Correct
and
Remove Keystoning
A minimalist approach to
photographing your art
By Paul Marley
Taking the Photograph
• Early morning or afternoon on a sunny day
but do the photographing in the shade
• Any decent digital camera should do
• Set at the highest resolution available
• Try to put something next to the object that
has a clean White or Gray or Black (or any
combination of the three you can make)
• Fill as much of the frame as possible
(remember you can rotate the image later)
More taking the Photograph
• The main objective is to make sure the
white (or lightly colored) areas do not get
too bright
• If the camera has Manual controls you
want to make the photo just a little too
dark
After Photography
• The following procedure can be done with
various versions of Photoshop and
Photoshop Elements
• Lets go!
Getting started
• Open your image and start with a
“Save As” and change the file type to .tif
The Info palette should always be referenced while
using curves. It shows the R (red), G (green), and
B (blue) values for any area in the image.
It will also show you values in the C (cyan)
M (magenta), Y (yellow) and K (black) for those
same areas. These four values are used by the
Offset Printing Industry. (Don’t worry about these)
You can see the X and Y coordinates of any desired
pixel within the image and get the W (width) and
H (height) when using the Measure Tool.
Make sure this palette is showing, go to
Window – Info and click it.
Do the same for Layers if it is not showing
Select Eyedropper Tool (I), set sample size to 3X3
then place the cursor somewhere (those White/Gray/Black areas would be best)
on the image to read values
Info reference markers can be placed anywhere in the image. Select the
Eyedropper Tool, press the Shift key and click the mouse while over the
area you want to mark. The values of the area will display at the bottom of
the info palette with a marker number. These markers will not print and can
be removed by clicking and holding on them while in the Eyedropper Tool
and dragging them out of the image area.
To adjust the color you need
to manipulate the
Whites/Grays/Blacks in the
image in balance. This will
bring the color to where it
needs to be.
In the Layers Palette there
is a button at the bottom the
looks like a half black half
white circle. Click on it and
you will see some options.
Select Curves
Curves allows you to manipulate
the colors individually or
simultaneously.
The values you are trying to reach
are:
Highlight (white) – 240
Shadow (black) – 25
Info marker should be placed in
these areas where detail can be
seen.
Total white – 255
Total Black – 0
The Curve of the image is set up
with the bottom left being the
Shadow point, the middle being
the Midtone and the top being
the Highlight.
To control a point on the curve,
click and hold it with the mouse.
Move the Shadow point to the
right to increase darkness. Move
it up to decrease darkness.
Move the Midtone up and the
image lightens down and it
darkens.
Move the Highlight to the left to
brighten and down to darken.
The image will show the change as it is made.
As you move the Curve you will notice the values are now indicated as:
208/191
The value left of the backslash is the original value while the other is the new
value.
When you have balanced the values for the markers you set click OK
You now see the Adjustment Layer in the
Layer Palette.
Now make sure to Save!
Things to watch:
1. Major corrections may have to be made in multiple moves instead
of all at once.
2. Digital photographs don’t hold up well to extreme correction.
Artifacting (small random areas of color anomalies) will likely occur,
especially when brightening a dark image. Make initial exposures
as good as possible.
3. Place a Grayscale in image if possible for more accurate
corrections.
Squaring up your painting
or
How to remove the Keystone
Effect and get the edges strait!
Lets start with a few things you’ll
need for this part of the process:
Rulers: These are needed in order
to pull the guidelines used in
making perfectly strait edges and
square corners.
Turn on Rulers CTRL - R
or View - Show Rulers.
Set Background color to White by
clicking on the color selectors at
the bottom of the main tool bar.
The smaller pair of black and
white squares will reset the color
back to default. Do this.
Get the Zoom tool and
draw a rectangle on
one of the corners so
you can get in close
and make a good tight
selection of the edges
of the painting’s
canvas.
Click and hold on the Lasso
tool to get the Polygonal
Lasso to show and then
select it. You will use this
to go around the edges of
the canvas. One click on
each corner.
Even though you are
zoomed in as you move
the tool to the end of the
image it will scroll
automatically.
Work your way back around
to your starting point to
complete the selection.
• Zoom all the way out
CTRL 0 (Zero) so you can see the
entire image
• Get the Move tool (see left)
• Start in area of ruler Click and
Hold to pull guide out then
place it to edge of canvas
• Should "snap" to the closest
part of the selection
• Pull to far edges first then
closer the edges closer to the
Rulers
• You will see the edges that are
out of square
(see next image with guides
all set)
It sounds strange but to
fix the image you will
have to “Distort” it.
zoom into area to be fixed
Edit - Transform - Distort
•
Pull painting corners to the
corners defined by the guides by
clicking, holding and moving the
little boxes. Release when it is
correctly positioned.
•
Space bar changes the cursor to
the Hand so you can navigate
through (by clicking, holding and
moving the Hand moves the
image) the image to fix the next
corner
•
Adjust all four corners if necessary
the double click inside the "Distort"
area and it will finalize the
changes.
• The selection area will still
show now make sure your
background color is white
• Then Select - Inverse will
select everything around the
painting but leaving the
painting untouched
• Then go to Edit - Clear and a
white background will now
surround the painting.
• Then Select – Deselect to
remove the selection
Then select the Crop Tool and draw a rectangle around the image leaving a small
border (if desired) The area that will be removed will turn dark gray. It can be
tweaked if required by moving the boxes found at the corners and sides. Then
double click within the cropped area and the crop will finalize.
Got to
View – Clear Guides
• Save image
• Done!
• Congratulations