Photoshop for Photographers
Clark College
Instructor
Garry T. Stasiuk
DPI
DPI (Dots per inch) has nothing to do with the resolution of a
photograph. DPI only provides information to a printer as to how many
dots to print per inch or tells the monitor how many dots per inch to
display. Today's monitors are set at either 72 DPi or 96 DPI
Camera Raw
Adobe's Camera Raw Plug-in supports unique raw file formats for 17
camera manufacturers and over 200 different cameras. Adobe has their
own raw file format called .DNG (Digital Negative)
White Balance and "Camera Raw"
When you shoot in "raw" format you have total control over white
balance. In Adobe's Camera Raw or in any other image processor you can
change the recorded White balance to any value from ...
2000 K
to 50,000 K
These settings are for final output to an inkjet printer, but, if you set the clipping points in Camera Raw... Do not change the Black and white points!
R,G,B at 0,0,0 is the value for black ink. By spreading out
the black values we avoid pooling the black ink. (The darker the color
the the greater the amount of ink the printer sprays on the paper)
R,G, B at 255. 255, 255 is white (no ink), lowering the white
component reduces the possibility of have large areas of the canvas
with no ink spay at all...
The setting (133) adds a little 'punch' to the mid-tones....
Here's another tidbit for you, and a real good reason to upgrade to
the latest Photoshop software ---prior to CS3 and PSE 6 and Lightroom
1.3 The Contrast and Brightness controls were broken and never really
worked as they were supposed to...!!! Hence the warnings about using
contrast and brightness controls sparingly, if at all.
In Photoshop Elements there are no curve adjustments... so if I suggest using curves... In PSE use Levels instead!
Image Processing.
Rule #4: Do not
assume..that if the picture you are photographing doesn't turn out, you
can fix it in Photoshop, ImageFX or some other
image processing software. You will be sorely disappointed! Remember,
with a digital camera, you don't use film... you can shoot until you
run out of storage memory and you can always delete (heaven
forbid) failed pictures.
Always remember this Absolute Rule: Do Not, not ever, Throw Away Data!
- Use contrast and brightness controls carefully and sparingly as
these tools changes whole pixel values... you actually wind up throwing
away information when you save the result. In other words, the data you
changed using contrast and brightness is a one way street...there is no
way to get back to the original data set.
- Use and exaggerate color balance controls: R, G, B, or Hue / Saturation, or CYMK
- These functions control or manipulate data in the colour look up
table, only changing their values not not throwing them away. You can
reset or revert the "color look up data" back to its original state,
even after you have saved the changes.
- Do Not Throw Away Data
- Never change image resolution.
- Yep, you got it, Do Not Throw Away Data.
Level Controls
You can use "Levels" to adjust color tone The test picture was shot in
Guadalajara, Mexico on a dark sunless street, right around sunset,
using a Nikkormat FT2 with a Vivitar f/2.8 28 90mm lens on KodaChrome
64 slide film.
Ugh, it's way dark...The fix is to work with the mid grays. this is
done using the "Levels" function and the sliders under the histogram's
bell curve.
Here's what the controls do in The "Levels" Dialogue box
Don't forget to flatten and save the "enhanced" picture.
For an excellent getting up to speed tutorial on using PhotoShop go here...
http://luminous-landscape.com/tutorials/instant_photoshop.shtml
Here's the details about the curves Dialogue box...
Layers
How it works...
http://www.photoshopcafe.com/tutorials/layers/Layers.htm
A tutorial for fixing Under and over exposed photos
Overexposed Instructions
