[ 彩材拆拆 x UNWRAP CMF ]
Ch.44 Unwrapping CMF design on why oh why color difference?
Ch.44 拆招CMF設計談為什麼你的產品有色差?

CMF is a specific discipline within industrial design that focuses on the development of a product’s color, material, and finish. Unwrap CMF shares bite-sized stories of CMF Design to inform and inspire those interested in this niche yet fascinating field, with digestible contents for anyone and everyone. Comments and inspirations are welcome!

In previous chapters, we learned that mass production cannot achieve 100% consistency with the golden sample. The role of CMF is to determine a feasible limit range that considers both production practicality and visual appeal, serving as the standard for saturation, brightness, gloss levels, and other visual parameters. (中文請見下方)

Controlling the color formula for the same materials and processes is already challenging, let alone when different materials or processes are used on the same product. Metal color differ in brightness and lightness due to its angle-dependent reflection. That means, even if the anodized metal part can match nicely to the magenta color of an injection plastic, metal color can still differ at different angles.

陽極金屬即使與射出塑膠同色,由於不同角度的反射,仍可能造成鮮豔度和明暗度的色差。
Anodized metal matching plastic’s color might still differ in brightness and lightness due to angle-dependent reflection.

You might think it would be easier for black, gray, and white. But it’s not. Even the slightest color difference will be a lot more noticeable compared to other colors.

At factories, part inspection (also known as Quality Control) and parts assembly are handled by different teams, handling their tasks indepedently. While very few high-investment factories would purchase automatic color detection systems, most assembly lines in reality cannot afford additional labor or equipment. This makes controlling color differences in actual assembly not as easy as one might imagine.

If two parts happen to be at the extremes upper or lower of their limit ranges, when they’re put together, there will be very noticeable differences in color.

Now, the questions is: Is there anything we can do? Yes! Imagine these scenarios:

Scenario One
Golden sample: C
First part is ranged between color A, B, and C
Second part is ranged between color C, D, and E
The maximum color difference between the two would be A to E (4 tiers away)

Scenario Two
Golden sample: C
First part is ranged between color B, C, and D
Second part is ranged between color B, C, and D
The maximum color difference between the two would be B to D (2 tiers away)

This reminds us that if only golden sample is the only reference, huge color gap can occur between different parts. Therefore, when approving samples, we need to not only refer to the golden sample, but also cross-referencing the limit boards of other parts of the same product.

This will ensure that each part’s range stays within the same standard, so the efforts already spent on color-tuning for each material and process will not go to waste.

兩個零件若位於各自限度範圍的極端,在當它們被組裝在一起時,就難免產生顯眼的色差。
If two parts are at the extremes of their limit ranges, assembling them together will result in noticeable color differences.

Continue reading:
Ch14. Unwrapping CMF Design on Unavoidable Color Differences
Ch18. Unwrapping CMF Design on the Little White Lie
Ch31. Unwrapping CMF Design on Colorimeter, Yes or No?

CMF為Color Material and Finishing,屬於工業設計旗下專注於產品色彩、材質、及表面處理工藝的關鍵一環。Unwrap CMF彩材拆拆圍繞著這個主題,以淺而易懂的小故事拆解CMF設計的日常。歡迎留言分享!

在之前的文章中,我們了解到量產中無法完全達到標準樣(golden sample)的百分一百一致。CMF的職責便在於定奪一個既符合量產可行性又兼顧視覺效果的限度範圍(limit range),以此為基準判定鮮豔度、明暗、光啞等的外觀標準。

然而,要掌控相同材料及製程的調色配方已然不易,更何況是運用不同材料或製程。同為桃紅色,即使陽極金屬能做到與射出塑膠同色,但金屬在不同角度下的反射會產生不同的鮮豔及明暗,進而增加兩者之間的色差。

而就算是「純粹」的顏色,如黑、白、灰,也並不比其他顏色簡單,任何微乎其微的色差都會比其他顏色更加明顯。

白色並不比其他顏色簡單,任何微乎其微的色差都會比其他顏色更加明顯。
White isn’t any easier. Even the slightest color difference will be more noticeable compared to other colors.

在工廠端,品質檢驗QC(Quality Control)和零件組裝是不同的團隊,各司其職。儘管少數高投資的組裝線可能配備了自動辨色系統,但多數的組裝線並無法投入額外的人力或設備,因此在實際生產組裝中,色差的掌控並不像想像中那麼容易。

如果兩個零件的限度範圍各自有異,又剛好處在彼此限度範圍的極端,當它們被組裝在一起時,就難免產生非常顯眼的色差。

那…我們還可以做什麼?試想以下情況:

情況一
標準樣為C
一號零件限度範圍為ABC
二號零件限度範圍為CDE
兩者最大色差距離為A~E 四個色階之差

情況二
標準樣為C
一號零件限度範圍為BCD
二號零件限度範圍為BCD
兩者最大色差距離為B~D 兩個色階之差

這提醒我們,如果在簽樣時只單單參考標準樣,不同零件也可能出現極大的色差。所以在簽樣時,除了參考標準樣之外,也要反覆比對同個產品、不同零件的限度版(limit boards),以確保每個零件的限度範圍都在相同的範圍標準內,才不會枉費已在材料和製程上投入的調色心血。

兩個零件若位於各自限度範圍的極端,在當它們被組裝在一起時,就難免產生顯眼的色差。
If two parts are at the extremes of their limit ranges, assembling them together will result in noticeable color differences.

延伸閱讀:
Ch14. 拆招CMF設計談難以避免的色差
Ch18. 拆招CMF設計談不分青紅皂白
Ch31. 拆招CMF設計談色差儀要不要?




CMF學無止境,善用CMF關鍵字在網上深入鑽研,歡迎大家留言補充。
Enjoy learning? Use the CMF terminologies mentioned above and continue on with your own research journey on the web. Comments and inspirations are welcome!
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Problem-solving ??? ?????. Former head of CMF at Motorola. A New York-based and world-traveling Design Consultant with over 13 years of specialty in CMF Design. 高雄囡仔,前摩托羅拉CMF設計團隊負責人,目前定居於紐約並遊牧世界,任自由撰稿人兼CMF設計顧問,持續投入在CMF設計的科普推廣,並為WGSN及羅技等公司提供CMF專案支持或諮詢服務。

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