The Color Variance in A Printing Service
Due to the complex nature of reproducing a full spectrum of colors by blending 4 colors of ink (Cyan, Magenta, Yellow, and Black), all 4-color printing is subject to some small degree of color variance. This means that specific colors may look slightly different from the beginning of a run to the end of the run, and differences become more noticeable between different printing service.
4-color offset presses are able to reproduce colors far more consistently than digital or print-on-demand presses, but the blending of inks means that there will always be some variance. This variance is most noticeable between different runs of the same project, as in the photo below:
For individual color that need to be exactly the same every time, the color can be guaranteed by the use of a spot color ink for a job more than 1000 sheets (it will be 4000~8000 cards in a postcard printing). The specific color to be matched is most commonly specified using the Pantone Color Matching System.
Why the color looks different
The color will look differently depending on a variety of factors:
1. The color model used in the artwork (RGB vs CMYK)
In most cases, the RGB colors we see on screen are brighter than the CMYK color on printed items.
2. The printing process used (digital vs offset)
Since the digital&press printing are made with different process and equipment so they are likely that looks different. However, in some cases with professional color matching system, the could be 90% same.
3. The material printed on (paper, vinyl, fabric)
4. The texture or finish of the product (coated or uncoated paper stock, original color of the paper)
The color on coated papers is usually brighter than uncoated papers.
5. The number of sheets in a run
The most stable colors are produced in the middle within a printing job. So the color variance happens more often in small volume orders. The specific color in the beginning of a run and end of a run are likely to be different. For small orders(e.g. 200 sheets), it’s a very short time to finish the run(less than 5 mins), so the colors are not stable in a short run
6. The environmental lights around the printed item
Under warm light, the color looks more red&yellow; under cold light, the color looks more blue; The following is the same printed sheet under different light.