Preparing-Digital-Images

District Chapter 109

Metro Washington DC

Information and Instructions for Editing & Resizing Digital Images

NOTE: These instructions for for Windows/PC users.

CaFE: There are 7 edits you must make to your images before you can upload them to CaFE:

Make sure the image and the original look the same

Set the resolution to 72ppi

Place the image inside a 1920 x 1920 pixel square

Fill the excess canvas with black

Make sure the mode is RGB

Rename the file to meet CPSA specifications

Save the file as a .jpg

To help you do that, this demo will cover the fundamentals of file sizes, some basic editing functions (mainly cropping and lighting), and the conventions of files names and formats.

FILE SIZES - There are 4 ways file size is defined:

Height & width in inches (e.g., 5” x 7”)

Height & width in pixels (e.g., 1920 x 1920)

Resolution, stated as pixels per inch (ppi)

File size in bytes, which is the total amount of information contained in the file

And they are all interrelated

Inch measurements are self-explanatory and matter only when you plan to print an image.

Pixels are the building blocks of all digital images and are what you’re seeing when you view an image on your computer’s monitor or on a TV. Pixel size is stated so many pixels across (width) and so many pixels down (height), just like inches. So a file that is 288 pixels x 150 pixels has 288 pixels across and 150 pixels down.

The difference between inches and pixels is that the size of an inch is absolute, while pixel size can vary. Understanding that is key to understanding resolution.

Resolution (ppi) is about the size and number of pixels packed into each inch. So in a file with a high resolution of 300ppi, the pixels will be much smaller and more densely packed into each inch than a file with a low resolution of 72ppi. What does this mean? It means a 72ppi image will look fine on your monitor or printed at a small size (like 2” x 3”), but if you try to view or print it larger (like at 8” x 10”), the image becomes blurred and “pixelated.” That’s because the computer either has to invent those extra pixels (called “resampling”) or increase the size of each of the 72 pixels in each inch.

Total file size refers to the amount of space a file takes up on a storage device and is stated in kilobytes (KB), megabytes (MG), and gigabytes (GB). It takes more memory to store more pixels, so higher resolution and larger-sized files take up more room. For example:

A 72ppi file that is sized at 4” x 3” is a small file, usually around 100KB.

A 300ppi file that is sized at 4” x 3” is a medium file, around 1MB.

A 300ppi file that is sized at 9” x 12” is a large file, around 4MB.

ABOUT RESIZING IMAGES

It all starts with your camera: the camera’s megapixel capacity (the number of actual sensors behind the lens) and the “quality” settings you select will determine the size (in pixels and inches) and the resolution of the images it takes. Set the camera to take the highest quality photos it can: you get the best results by sizing down, from a high resolution file to a low resolution file.

The best size for posting on the web (to photo-sharing sites like Picasa or Flickr, or for our DC109 gallery) is 72ppi and about 288 pixels on the longest side. This means that we don’t use up a lot of storage space on the site’s servers, and it also means that if anyone tries to download your image, they can’t do much of anything with it. The best size for printing is at a higher resolution (240-300ppi) to maintain image quality and fidelity.

FILE FORMATS - There are a number of different file formats in use, and a file’s format is indicated by the extension that follows the filename (e.g., Summer.jpg). The main difference among them is the way the data is stored and displayed, which also affects file size. The main ones you need to know are:

.jpg: compresses data when it’s stored, so files sizes are smaller. Jpegs are the standard for most users and for the web (keep in mind that some small amount of data is lost every time you open, edit, and close a .jpg file)

.tif: uses less compression as it’s stored and file sizes are therefore larger. Keep your master images as tifs; you can copy them as .jpegs for editing and posting, and you'll always have that high-resoluion .tif when you need it...

COMMERCIAL SCANNING - If you take your work to a commercial photographer to be scanned, you want them to give you a variety of files of different sizes, instead of just one big file, so that you don't have to worry about resizing that big file later on for different purposes. Make sure you tell them whether you have a Mac or a PC, and ask them to give you three files for each image, all three files on one cd (one cd per image):

1. The first one should be a .tif file, 300ppi, and between 7 and 9 inches on its longer side. This one will be your primary high resolution record copy file, which is useful for any printing application (like for postcards). Have them name this file with the title of the drawing. (So if the title of your drawing is "Springtime," the file name should be Springtime.tif .)

2. The second file should be a .jpg file, 72ppi, and 288 pixels on its longer side. Have them name this file with the title of the drawing, then an underscore, then "web". (So if the title of your drawing is "Springtime," the file name should be Springtime_web.jpg .) This is will be the file you upload to a photo-sharing website or send for posting on the DC109 website.

3. The third file should be a .jpg file, 72ppi, and 1920 pixels on its longer side. Then the canvas size needs to be set to 1920 pixels for the shorter of the two dimensions, so that the image is now in a box that's 1920 x 1920 pixels. The extra canvas space (the part of the box that does not contain your image) must be filled with black. Have them name this file with the title of the drawing then an underscore then "cafe". (So if the title of your drawing is "Springtime," the file name should be Springtime_cafe.jpg .) That way you'll know it's the one to upload to the CaFE website for submission to the CPSA international show, according to their specs.

When they give you the cd with these three files on them, you should be able to just copy each file from the cd into your filing system (you need a filing system!) and they’ll be ready for you to use.

IF YOU TAKE YOUR OWN PHOTOS - You’ll need to be able to do some basic editing to prepare them for submission to CaFE (those 7 things at the top of this page). Attached are instructions for performing these tasks on a PC using Photoshop Elements (available for about $90 at Amazon or less on eBay) and GIMP ( GNU Image manipulation Program: available as a FREE download from the internet).

Some photo-shooting basics:

--Make sure your image is parallel to the camera

--Make sure it’s well lit but no flash

--Shoot it unframed, and zoom in to include as much image as possible and as little anything else as possible

--Set camera to “best” (“finest,” “highest,” etc) resolution and set white balance to match your lighting

--Put the camera on a tripod

PHOTOSHOP ELEMENTS (this is based on the older 5.0 version, but should work for newer versons, too)

OPEN

File --> Open… then click on the image you want to edit and click Open

NOTE: Either work on a copy of your image or be sure to use “Save As” when you’re done!)

ADJUST COLOR & LIGHTING

Enhance --> Adjust Color --> Remove Color Cast

Click on an area in the image that should be white and watch the image adjust. If it looks good, click OK.

And/Or you can use

Enhance --> Adjust Lighting --> Levels

This gives you a histogram that shows the distribution of values in your image. You can adjust the lighting and contrast by moving the black, gray, and white markers under the histogram to the right and left. Once you’re happy, click OK.

NOTE: If at any point you change your mind, go to Edit --> Undo to undo the last change you made.

CROP

Select the Crop tool from your toolbox (the little view-finder-looking thing). Place your cursor at the upper left corner of the image, where you want the crop to begin. Hold the left mouse button down while you drag the cursor down to the lower right corner. This establishes the area that will remain after cropping. If you want to adjust it, put your cursor on any of the 8 marked points and hold the left mouse button down while you drag the box to where you want it to go. Once you’re happy, click on the check mark (“yes”); if you want to start again, click on the “no” symbol and start over.

RESIZE

Image --> Resize --> Image Size

First, make sure the “Constrain Proportions” and “Resample Image” options are both checked (resample method should be “Bicubic”).

In the Document Size box, make the resolution 72.

In the Pixel Dimensions box, make sure the setting to the right says “pixels” and then make the longer side 1920 pixels. Click OK.

CANVAS

Image --> Resize --> Canvas Size

Set it to pixels, then reset the shorter side to 1920 pixels. The anchor below will show you where the image will be placed: make sure it’s in the center. Go down to Canvas Extension Color and from the drop-down menu, select black. Click OK.

MODE

Image --> Mode

Make sure “RGB Color” is checked

RENAME AND SAVE

File --> Save As

First look at the “Save in” box at the top: that’s the directory & folder where the file will be saved: make sure it’s where you want it to be saved!

Filename should be Title 1of2 or Title 2of2, to meet CPSA specs

Format should be JPEG

Then hit Save. In the JPEG Options box, set it to “large file” and “maximum” then click OK.

GIMP

GIMP is available as a FREE download from http://www.gimp.org/downloads/ or (recommended) from www.sourceforge.net.

OPEN

File --> Open…

The first time you use GIMP, it won’t know where to look for your photos, so you have to navigate to the folder where you keep them. Once you do that the first time, it will remember and display the pathway at the top. If you don’t know how to get there, go down to “Start,” click on “My Pictures,” and then you will see the pathway at the top of the window that opens.

For me, for instance, it says: C:\Documents and Settings\Owner\My Documents\My Pictures and within “My Pictures” I can find the files I want. Once you’ve gotten to the right folder, click on the image you want to edit and click Open.

NOTE: Either work on a copy of your image or be sure to use “Save As” when you’re done!)

ADJUST COLOR & LIGHTING

Colors --> Levels --> Input Levels

NOTE: If at any point you change your mind, go to Edit --> Undo to undo the last change you made. Go to Edit --> Undo History to be able to track all your changes in the right-hand pane. In that pane you can go back to any stage of editing just by clicking on the stage you want, if you have not saved the file yet.

CROP

Select the Crop tool from the Tool Box on the left (looks like a craft knife). Place your cursor (the center of the four little hash marks) at the upper left corner of the image, where you want the crop to begin. Hold the left mouse button down while you drag the cursor down to the lower right corner. This establishes the area that will remain after cropping. If you want to adjust it, put your cursor on any of the marked corner points and hold the left mouse button down while you drag the box to where you want it to go. Once you’re happy, press Enter to complete the crop.

RESIZE

First, you may want to find the little button under the editing pane that lets you change whether the rulers at the top and left measure in inches or pixels: click on it and select pixels. This just helps you see what you're doing.

Image --> Scale Image --> Image Size

Change the unit of measurement to pixels if necessary. Make the longer side 1920 pixels.

For the X and Y axis boxes, first make sure the measurement is pixels/inch; then set one of the resolution boxes to 72.000 (the other will reset automatically).

Click Scale

CANVAS

Image --> Canvas Size

Change the unit of measurement to pixels if necessary. Then click on the little chain links icon to the right of the two boxes, to uncouple the two measurements (otherwise any change to one measurement automatically resets the other measurement, which you don’t want). Reset the second dimension to 1920 pixels.

Click Center

Click Resize

This will create the extra canvas with yor image centered: now you have to make it black. Look at the left-hand pane, where the tools are: below the tools, you’ll see two little boxes, one black, one white. If you hold your cursor over them, you’ll see those boxes set the foreground and background colors. The default for the background is white: click on the little “swap” arrows to reverse the two and make the background black. (You won’t see a change until the next step.)

Then go to Image --> Flatten Image. As soon as you click on “Flatten Image,” voila! The canvas will turn black!

MODE

Image --> Mode

Make sure RGB is selected (a dot will be there) and hit OK.

RENAME AND SAVE

File --> Save As

Name should be Title 1of2 or Title 2of2

Save in folder: Use the drop down menu to save the file in the right directory and folder (where you can find it again)

Click on the little + button to the left of “Select File Type (By Extension)” and then scroll down to and select “JPEG Image”

In the “Save as JPEG” box that appears, move the Quality toggle to 100 and click Save again.