You know what we should talk about more in this industry? How to prepare images for variable-data workflows. We talk about the data portion of VDP. Why don’t we talk as much about images?
Recently, I decided to do just that. I put a question to a group of experts: “What challenges you encounter with variable data images and what mistakes do customers often make in preparing them for a VDP workflow? What can customers do in order to make the process seamless?”
Here are the answers they gave. Did they miss any?
- Are the images standardized/normalized?
- Check color space (CMYK/RGB)
- Resolution (Min/Max)
- Format (JPG, TIFF)
- Aspect/Scale (height/width ratio)
- Is the content consistent?
Do images contain equal white space around them? Or are they all cut out to the edge? If the layout is not dynamic, are they all cropped to the right orientation (horizontal/vertical)? Are the products facing the right direction?
“Details that seem minor in the beginning can end up huge at the end of the press. Even something as simple as which direction a person is looking can make or break an individual piece, if not an entire project.”
- Are the images available in the database?
Images can get moved or renamed, and if the DFE goes to pull an image and cannot locate it, this can spell disaster for the project. It’s worth the time to doublecheck—every time.
- Are they optimized?
“Reducing image size and optimizing sharpness to optimal resolution will create good print quality and reduce processing time in the DFE. If PDF files are used as background, or even as variable images, it is even more important to optimize. Remove unnecessary and invisible items. If possible, flatten them.”
- Are they too large?
We frequently think about images not being of sufficient size for high-quality reproduction, but when it comes to variable data, they can be too large, as well. If the images are larger than they need to be, they can bog down the RIP. According to the PDF Association, a delay of half a second on every page of a 10,000-page job running at 120 ppm adds 30 minutes to the entire job. For a job of one million pages at 5,200 ppm, even an extra tenth of a second per page adds 24 hours to the total processing time.
- Check ICC profiles and UCR/UCA/GCR.
- Crop images to the frame.
In a VDP workflow, images are automatically anchored in the upper left-hand corner of the image box. If they are not pre-trimmed to fit the space, the DFE will trim them for you. There are some decisions that should not be left up to a piece of software.
Is this a complete list? What is your experience with these issues? Is there anything else you’d add?
Aspect/Scale (height/width radio) –> could be ‘ratio’ 🙂
Good catch. Thanks.