Resolution, Color Management
Digital cameras measure the image size not in pixels per inch but instead, its
measured in megapixels. A megapixel is simply 1 million pixels.
To find out how many megapixels you
need to create a particular image size,
in Photoshop’s image size dialog box
you set the resolution you want and the
image size you want.
Multiply the number of pixels together.
In the example to the left you would
need a camera that had 6.5 megapixels
(2179 x 3000 = 6,537,000)
300 pixels per inch (ppi)
means how large a
pixel is when you print
it , and it usually is
measured in pixels per
100 pixels per inch (ppi) inch.
More pixels per inch
1 inch means higher
30 pixels per inch (ppi)
How high of a resolution do you need?
That will depend on what medium your image is viewed in such as monitors,
printers, scanners, digital cameras. Unfortunately, there can be confusion because
the terminology for different devices can vary (ppi, dpi, lpi, megapixels,
and so on.) Sometimes we use lines per inch because “dots” aren’t used to make up
the image such as in “half tones” used in newspaper work.
Some Common lpi Settings:
85 lpi Newspaper Advertisements
100 lpi Newspaper Editorial section
133 lpi Magazines and brochures
150 lpi High-end magazines and high quality brochures
175 lpi Annual reports and high end brochures
53 lpi 300 dpi Laser printers
106 lpi 600 dpi Laser printers
212 lpi 1200 dpi Laser printers
You’ll get very high quality results on most injet printers if you
use images with resolution settings between 240 and 360 ppi.
Anything over 360 is just overkill.
You probably won’t even notice the difference between 360 ppi
and one with a higher resolution even if you use a magnifying
glass to compare them.
If you work with textured papers you might want to use closer
to 240 ppi and if you use a glossy paper you might want to use
360 ppi. My general recommendation is to to split the
difference and use 300 ppi if you are unsure.
Resampling will change how large the pixels are that make up the image. Any
changes you make to the resolution setting when the resample box is checked will
make the pixels larger or smaller, but the image will stay the same overall size.
This might be useful if you have a high resolution image going to a low resolution
medium. By making that change the file size would become less and that can be
very useful in many different ways. Lowering file sizes for the purposes of the web
will allow images to “load” faster in a browser and in printing it will lessen the
time it takes to print.
Caution is advised however as once the image is resampled to a lower resolution
you will not be able to resize it back to a larger size since you “threw away” pixels
to get the image smaller. Trying to make it bigger will result in a pixelated image.
Notice in this example that is not
resampled. By changing the
Resolution you change the size of
the image but the number of pixels
stays the same.
Digital cameras frequently give a
default setting of 72 ppi but the
image is quite large. If you change
the resolution to around 300 ppi the
image size will be quite a bit smaller
(typically 4 x6 inches.)
Sharpening the Image
The last thing you’ll do before sending your image to its final destination may be to “sharpen” the
image. Most images NEED sharpening. However, its important to understand what that means. You
will go to the “Filter” section under the menu bar to find the “Sharpen” commands. You do not use
“Sharpen”...you will use “Unsharp Mask”. Oddly named, its is a remnant from techniques used in the
printing industry in the past.
Unsharp mask puts a “halo” around each pixel to make
it appear sharper. If it is done in the correct proportion it
will improve the appearance of the image. If it is
overdone it will be apparent and lessen image quality.
Different mediums will require different levels of
There are 3 settings in the Unsharp Mask dialog box.
Amount, Radius and Threshold. The Amount is
measured in percent and you can go above 100%
without harm to the image. Radius refers to the how
much space will be used for the contrast boost between
pixels and the setting should probably should not
exceed 1.5 pixels. Threshold determines how different
two colors have to be for “sharpening” to kick in.
Threshold set at 0 will sharpen everything. You should
view your image at 100% size while sharpening.
Color Management & Printing
How do you make a print that looks the same as it does on the monitor?
Through color management.
The big problem with color is trying to get everyone to agree what color a
color actually is....Buy three Red felt tip markers from three different
manufacturers and see if they all look the same. Walk into a store to look at
different televisions from different manufacturers and see if the pictures all
look the same.
In order to get accurate color throughout the process, all of the devices used
must be “profiled” so that they know how one another interprets color.
All of the monitors in this lab have been profiled using a sophisticated
calibration device & software. You should calibrate your monitors at home if
you intend to work there and expect half way accurate color here.
All of the printers used here have had all of the papers commonly used here
“profiled” with the same sophisticated device and software used on the
Doing these things is only the beginning.....
Make sure your image is “tagged”. The photo lab’s computers should be set
up to embed a profile of Adobe RGB 1998 automatically. In Photoshop you
can set that up under Edit > Color Settings
You’ll need to make sure that several dialog boxes all are in agreement about what kind of file you are
using, what kind of paper you are printing on and even what printer you are printing on. Whenever you are
printing you will want to start the process by clicking on the “Print” button under File in the menu bar.
After you push the “Print” button you’ll see this dialogue box.
Check to make sure that all of these boxes are set as below. One exception is the
Printer Profile setting....it should state the Type of paper your are using..
You will change this to a Paper Profile!
Clicking on the “Printer Profile” tab brings up a large number of choices. You need to select the
one that matches the specific paper your are using. If you don’t...your picture will not be color correct.
The paper & Ink types are listed using a code...Enhanced Matte Paper = EMP
Premium Luster Paper = PLP, Photo Black ink = PK, Mate Black ink = MK etc.
Click on the “page set up” button to be sure that your printer is selected,
the right size paper is selected and that the image is properly oriented on
When you push the “Print” button you’ll be given yet another dialog
box where you must check a couple of other things. The first is to
check the “Print Settings”
The “Print Settings” dialog box looks like this. You should make sure that the
“Media Type” agrees with the paper you are using, that the ink is set to “color” if
you are making a color print and that the “Mode” is set to the Advanced settings
with Print Quality at “Superfine 1440”.
You will need to back track to where you saw “Copies & Pages” and
go down to “Printer Color Management”
You will see a box that allows you to make “color adjustments”. But
you don’t want to use them!
Since you are making your color adjustments within Photoshop you do not want
the printer to do anything other than what you’ve told it to do. You will click the
“No Color Adjustment” tab and then the Print button to start printing.
If you let Photoshop determine the color
turn this to OFF
If you have followed all of the steps
mentioned previously you should end
up with a print that looks very close to
what you see on screen. If your print
looks vastly different than what you
see on screen... chances are very good
that you’ve neglected to make all of
the proper settings agree with one
another. You should double check to
make sure that you have selected all of
the proper settings.