Color QC and Matching Blog

Color Me Stressed Out

If we put you under the spectrophotometer now, would you show up in deep shades of recession blue? Perhaps.

Tough economic times often mean having to make do with fewer resources to handle the workload. The same workload for developing new colors, adjusting production batches, and approving colors is spread over fewer people. Staff become stressed and can easily overlook color shifts they might otherwise have caught.

And, as you know, color shifts take time to correct. They result in product that either has to be reprocessed or worse, discarded, let alone the time and labor required to make the corrections.

Sometimes, it's the more experienced staff-the more expensive staff-that had to be let go, and along with them, went years of knowledge of how to work the color matching system or operate older, more finicky equipment.

But, just like a painter who switches from brush to roller and roller to spray gun, an investment in the right industrial color matching or color quality control technology can help ease the burden while increasing productivity and reducing costs.

Don't paint yourself into a corner

Investing in technology is one way to keep up with demand while keeping payrolls lean. 

Consider these advantages from a new, up-to-date, industrial color matching system:

Fewer production adjustments: The software can automatically calculate and add colorant to bring production back on track.

• Optimized adds: Color matching software can find the one, optimal colorant to add to correct a batch.
• Batch size variation adjustments: Color quality control software automatically calculates accurate adjustments by weight or volume, or even when the batch amounts are not known.
• Faster estimating: Detailed production costing lets you provide estimates faster, beating the competition to the bid.
• Wider color range: Today's sophisticated industrial color matching software databases help you reduce the number of colorants in inventory while broadening the range of colors you can produce.

This recession will end someday (or so they keep telling us). In the meantime, consider how technology can increase productivity, lower inventory, and keep staffing costs in check. Then, focus on the future, one with a bright, sunny, yellow outlook.

COLOR TOLERANCES:

 

One of the more frequent questions we hear from suppliers is:  What should my color tolerances be?  The simple answer equates to what the client will accept in color variation in all directions of color space versus the color standard the supplier needs to match.  The importance of the client providing representative color standards will be the subject of a future blog.

In the seventies and throughout the eighties the majority of suppliers relied on the CIELab defaults of +/- 0.5 for *a / *b axis with *L tolerances of +/- 1.0.  The CIELab DeltaE default was 1.0.  These so-called box tolerances were applied to dark colors, light colors, pastel colors, or high chroma colors with the assumption that regardless of where color was in color space any change in color perceptibility or color acceptability for the color match was the same.  The issues with these default numerical tolerances were that the human eye could accept bigger differences in lightness and darkness of darker colors than in lighter colors.  The same could be said of the hue (color of the sample).  Light pastel colors were more susceptible to a noticeable color difference than darker colors.  Consider a light beige where the color shifts a numerical 0.5 towards the -b* axis (bluer).  Dependent on the product this shift may be unacceptable whereas in a dark brown or maroon color it may be totally acceptable.  There have been shifts of Delta L* (Lightness) of 3.0+ units in a dark royal blue that have been totally acceptable whereas the Delta L* tolerance of 1.0 would indicate it was unacceptable.  With these type analogies color scientists sought some way to apply weighting factors to better define color differences dependent on where the color was located in color space.

In the 1980's and 90's, color scientists developed improved color equations like CMC and later CIE2000 for determining a better way to define small color differences that were more perceptually uniform.  Both equations use elliptical tolerancing to define an acceptability ellipse for a point in color space.  The ellipses vary in shape and size throughout color space.  Both CMC and CIE 2000 DE use weighting factors for lightness, chroma (CMC) and lightness, chroma, and hue (CIE2000) that better correlate to color differences asa the human eye sees it.   The result over time has been that elliptical tolerances as defined by color difference equations like CMC and CIE2000 are widely preferred within the color industry as being superior in defining human color perceptibility and color acceptability.  However, box tolerances are still in widespread use due to their ease of use and the long and extensive color histories that companies have bases on them.

 There is no right or wrong answer.  It's up to the buyer and seller to negotiate what is acceptable and to clearly spell it out in terms of a color specification.