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By Philip Lawson

Digital Imaging 2. The Basics - Scanning and Printing The Master Image Working with Layers Working with Channels Black and White. By Philip Lawson. The Master Image. Choose an image that does not have too greater contrast range and is not burnt out.

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By Philip Lawson

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  1. Digital Imaging 2 The Basics - Scanning and Printing The Master Image Working with Layers Working with Channels Black and White By Philip Lawson

  2. The Master Image • Choose an image that does not have too greater contrast range and is not burnt out. • If a slide, ensure the image is clean, scratch-free and is in the scanner the correct way up. • Pre-scan and Optimise dynamic range of ALL three colours.

  3. Scanners • Scanners scan each pixel as a Red, Green and Blue value in the range 0 to 256. (or 0 to 65,535 is a 16-bit scanner) • The number of pixels is limited to the Optical capability, this may be • 2700 ppi for a slide scanner and • 600 ppi for a print scanner • Avoid any Interpolation

  4. The Perfect Image • It can be argued that a perfect image contains • Only one pixel that has:A red value of 1/256 • Only one pixel that has:A green value of 1/256 • Only one pixel that has:A blue value of 1/256 • Only one pixel that has:A red value of 256/256 • Only one pixel that has:A green value of 256/256 • Only one pixel that has:A blue value of 256/256 • Millions of pixels that have R.G.B values of X:Y:Z.

  5. The Perfect Image • The histogram (Combined Luminosity) would look like this

  6. The Perfect Image • The RED histogram would look like this

  7. The Perfect Image • The GREEN histogram would look like this

  8. The Perfect Image • The BLUE histogram would look like this

  9. The Im-Perfect Image • However, scanning an image that has too great a dynamic range may result in • Many pixels that have:A red value of 0/256 • Many pixels that have:A green value of 0/256 • Many pixels that have:A blue value of 0/256 • Many pixels that have:A red value of 256/256 • Many pixels that have:A green value of 256/256 • Many pixels that have:A blue value of 256/256

  10. The Im-Perfect Image • Contrast Range too HIGH

  11. The Im-Perfect Image • Contrast Rangetoo BIASEDto High Key

  12. The Im-Perfect Image • Contrast Rangetoo BIASEDto Low Key

  13. The Im-Perfect Image • ALL OF WHICH YOU CAN DO NOTHING ABOUT IF YOUR SCANNER ALLOWS NO ADJUSTMENT OF ILLUMINATION AND DYNAMIC RANGE. • What can you do anything about?

  14. The Im-Perfect Image • Contrast Range too LOW

  15. The Im-Perfect Image • Low Key,High Key butLow Contrast

  16. The Im-Perfect Image • Colour Cast

  17. Scanning • When Scanning, trim and adjust the dynamic Range of each Primary to its maximum • This should optimise the number-set for all further work • Ensure that there is a Black point and and White point • Eliminate general Colour Casts

  18. Once In Photoshop • Save as (O)MyPicture.psd (or tif) • Clean and Retouch • Crop if absolutely sure • Sharpen • Save as (M)MyPicture.psd (or tif)

  19. Clean and Retouch • Work at about 300% magnification from the Top Left hand Corner • Use the Clone Tool (S) • Use a SOFT brush of about size 15 • Clone from nearby (~3 brush widths) in the direction of nearest comparability (follow natural lines and diagonals) • Move Left and Right with Ctrl+Page Up/Down • Move Down with Page Down

  20. Clean and Retouch • Never use Noise, Dust and Scratch Filters as these tend to soften the image and reduce detail overall.

  21. Sharpen • Enhance Sharpness by using Filter->Sharpen->Unsharp Mask • Observe effects • Amount 100% - 200% • Radius 1 - 3 pixels • Threshold 5 - 10

  22. Sharpen • Sharpening in the RGB Mode causes Colour Fringing • Convert to Image->Mode->Lab Color • Select Channels Palette • Select Lightness Channel • Sharpen • Convert to Image-> Mode->CMYK Color • Save

  23. Catalogue • Catalogue all images by Image->Iamge Size to 1000 pixels on a side. • Flatten if Layered • Save as JPEG • Import into Catalogue Program

  24. End of Master Image Photographs courtesy of Janet Edwards

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