Sunday, April 22, 2007

Digital Workflow

Producing a digital file that is good enough to print is complex. Here is a set of steps that you can use to help ensure that you will a have a file that is suitable for high quality printing.

1 Shoot in highest resolution
2 Transfer photographs to the computer
3 Open the file in Photoshop
4 Assign a profile
5 Convert the file to 16 bits
6 Change resolution to 300 dpi
7 Adjust file in Levels
8 Adjust file in Curves
9 Adjust file in Hue/Saturation
10 Local adjustments
11 Crop
12 Retouch
13 Sharpen

1 With a camera of your choice shoot a series of photographs at the highest resolution possible. This would be highest quality JPEG on most cameras. With a camera that has both JPEG and TIFF options choose TIF. With cameras that have RAW file capability, choose RAW not TIFF or JPEG.

2 Transfer photographs to the computer with a card reader. This is the fastest and easiest way to transfer photographs to a computer. I use a USB card reader. It has no cords to plug in, needs no special software, is fast and was inexpensive.

3 Open the file in Photoshop.

4 Assign a profile

5 Convert the file to 16 bits by going to Image>Mode>16 bits/Channel. With JPEG files Save As a TIFF. RAW images are 16 bits.

6 Go to Image>Image Sizeā€¦ The resolution should be 300. To change it uncheck Resample Image and then click OK.

7 To adjust the brightness and contrast of a black and white image, or to adjust the brightness and color balance of a color image, Layer>New Adjustment Layer>Levels. "Levels" opens a complex window with several buttons and a graph. The graph is called a histogram and is showing the tonal range of the image with the shadows on the left, the midtones in the middle and the highlights on the right. The 3 little triangles running along the line below the histogram are referred to as the input sliders. The color of each one (black, gray and white) shows what part of the tonal range that each one represents. There are 3 boxes above the histogram showing the numerical representations of every tone in the image. 0 is jet black and 255 is paper white.

To the right of the input slider bar appear 3 eyedroppers. Notice once again that they are colored black, gray and white. Click on the white one which is the one on the right. When you move the cursor into the image you will notice it has changed from an arrow (or whatever else was the previous cursor shape) to an eyedropper. Click on the lightest area of significance. In other words, don't choose something like a bright white reflection off of a mirror or something similar. The image should look somewhat different after doing this and the histogram should change. Do the same with the shadows using the eye dropper on the left. For the midtones move the midtone input slider to the left to lower the contrast and to the right to increase the contrast. Ignore the midtone eye dropper. Click on the OK button to complete the procedure and then save the image.

8 Fine tune adjustments in Curves

9 Fine tune adjustments in Hue/Saturation

10 Make local adjustments with the Magic Wand tool.

11 To crop the image, go to the vertical tool bar and click on the top left icon. A sub-icon menu of five icons appears. Choose the one on the right. Take the cursor and place it in the corner of the image. Click and slowly drag to the opposite corner eliminating areas on each side that you no longer want. Click on return to complete the operation.

12 Remove flaws with the clone stamp tool

13 Sharpen the image

Filter>Sharpen>Unsharp Mask

Start with
Amount 300
Radius 0.7
Threshold 3
source: Digital Photography, 2nd Edition - Eismann, Duggan + Grey p 513 - 520

Start with
Amount 200
Radius 0.3
Threshold 0
use Optipix software set at Safe Sharpen
for both sharpening can be reduced with Edit>Fade in Photoshop
source: Digital Photography (2006) - George DeWolfe p 38

Amount 45
Radius 2.0
Threshold 1

You can preview the sharpening effect. Be careful not to oversharpen. When you oversharpen you will often see a strange grainy dot pattern somewhere in the image. Sharpening should always be your very last step in the editing process because it magnifies any image editing that has been done.


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