~ by Brad Schmidt, Colour Technical Support Specialist
When preparing images for print, using Adobe InDesign or Photoshop, there are multiple approaches to achieve the desired results. Each user may have their own preferences for solving specific problems, especially when making color adjustments. Some prefer using Curves or Levels, while others opt for Brightness/Contrast or Hue/Saturation. Although the end results may be similar, the paths to achieve them can vary significantly.
Choosing the Right File Format
Selecting the appropriate file format is crucial for print quality. Traditionally, TIFF and EPS formats were preferred, but with the adoption of InDesign, other formats like JPEG, PSD, and PDF have become more common. Each format has its advantages:
- TIFF: Ideal for high-quality images with no compression.
- JPEG: Suitable for web use but can be used for print with high resolution.
- PSD: Maintains adjustment layers, offering flexibility in editing.
Color Adjustments
Different users have varying preferences for color adjustments. Common tools include:
- Curves and Levels: For precise control over tonal range.
- Brightness/Contrast and Hue/Saturation: For quick adjustments.
RGB vs. CMYK
Choosing between RGB and CMYK color spaces depends on your project needs:
- RGB: Offers more flexibility and is suitable for digital screens.
- CMYK: Provides better control for print outputs.
Image Manipulation in InDesign
InDesign offers several tools for image manipulation:
- Cropping: Use only the necessary portion of the image.
- Rotating and Flipping: Adjust the orientation of your images.
- Scaling: Resize images directly within the layout.
InDesign vs. Photoshop for Scaling Images
To test the difference between scaling images in InDesign and Photoshop, an image was placed in InDesign and reduced to 10% of its original size, resulting in an effective resolution far beyond the recommended 300 ppi for printing. The same image was resized in Photoshop to 10% with a final resolution of 300 ppi. Both images were then exported to PDF using recommended settings, which downsample images to 300 ppi if they exceed 400 ppi.
Comparing Results
When comparing the two methods, the image resized in Photoshop maintained more detail than the one scaled in InDesign. The InDesign image appeared slightly softer. Applying an Unsharp Mask in Photoshop further enhanced the detail, making the text on the circuit board and the texture of the chip surface clearer. However, excessive use of the Unsharp Mask can result in halos along the edges.
At the end of the day, the choice between using InDesign or Photoshop for scaling images depends on the project’s quality requirements. Small percentage adjustments can be done safely in InDesign with minimal quality loss, while larger adjustments may benefit from Photoshop’s capabilities. As a general guide, consider using Photoshop for scaling adjustments greater than 20% up or down.
