Tests reveal color accuracy of new application

The Flemish Innovation Center for Graphic Communication (VIGC) conducted a study into the accuracy and reliability of the new myPANTONE for iPhone. With PANTONE describing itself as ‘the color authority’, expectations for the application are high.  

When I heard that PANTONE had launched a color reference tool for the Apple iPhone, I was somewhat surprised. The iPhone does not have a calibrated screen, so I questioned the accuracy of the on-screen color rendering. We at VIGC subsequently conducted a number of simple tests to check if the application could live up to expectations.

 

Two devices, two colors

We tested two devices with the co-operation of Apple Belgium, which kindly provided the organization with an iPhone 3G and an iPod Touch, which has the same screen as the iPhone 2G.   

After installing the myPANTONE application, we retrieved the color PANTONE GOE 37-5-1 C on both devices, with identical settings. This simple test immediately revealed a color difference. Plus the printed patch in the PANTONE GOE guide looked different to the one shown on the iPhones.

The iPhone 3G (left) and iPod Touch (right) show the PANTONE GOE 37-5-1 C color. The comparison shows that the colors are different.

Comparing the iPhone 3G with the printed GOE guide revealed a noticeable difference. 

When we compared the iPhone 3G – which features better color rendering than the 2G and iPhone Touch – with an LCD screen calibrated with the X-Rite Color Munki Design, there was a remarkable difference yet again. While this was partly caused by the glare of the iPhone screen, this also clearly illustrates the limitations of the iPhone and iPod Touch screens.

A comparison between the iPhone 3G and a calibrated monitor with a color gamut very close to sRGB. The iPhone 3G has a smaller color gamut, plus the glare of the screen plays a role in the color perception.

On the internet one can find ICC profiles that have been created specifically for iPhone 2G and 3G screens (read page via Google Translate). When comparing them in a gamut viewing tool, it is clear that neither of the two devices come close to sRGB (like most monitors used in an office environment), and certainly not close to AdobeRGB (like dedicated monitors for prepress environments). And while the iPhone 3G may have a bigger gamut than the 2G or the iPod Touch, it is still limited.

It is important to note that Apple has never claimed that the screens on the iPhone are sRGB or calibrated.

 

Snapping pictures to the closest PANTONE color

In its product information, PANTONE claims that it is possible to take a picture with the iPhone, or upload a picture to the iPhone, and ‘snap’ a selected color to a similar one in the PANTONE libraries.

We put this claim to the test. We made a picture of a color patch in the PANTONE GOE guide, the same color as that used in the first test. The picture was taken in a D50 light box. No shadow was cast on the patch, so as not to influence the results. The outcome was disappointing. The 'snapped' colour was 32-5-2 C – a totally different color, both on screen and on the printed patch.

VIGC took a picture of PANTONE GOE 37-5-1 C in the color guide and then tried the ‘snap’ feature. The two color patches show the 37-5-1 C color patch (left) and the perfect color match the myPANTONE software ‘snapped’ to (right).

It can be argued that such disparity can be attributed to the iPhone camera. So VIGC conducted another test. We uploaded to the iPhone an artificial image with the RGB values specified in the PANTONE GOE guide. Once again, the software snapped to a different color – 39-1-5 C.

A comparison of the original color (middle) and the colors that myPANTONE snapped to. On the left is the color from the photograph. On the right is the color from the – perfect – artificial image.

In addition to the 37-5-1 C color, VIGC also tested following the following colors: 1-1-7 C (Medium Yellow C); 23-1-7 C (Bright Red C); 70-1-7 C (Dark Blue C); 105-1-7 C (Bright Green C); and 165-1-7 C (Neutral Black C). For these colors, the VIGC noticed some remarkable color differences between the two devices.

Also, the comparison between the iPhone 3G and the printed GOE guide did not produce the expected results. For the green and blue colors, the results were at times highly divergent. The ‘snap’ test with the iPhone camera never came close to the original color. Similarly, the ‘snap’ test with artificial RGB images failed to deliver a correct result. For all six colors tested by VIGC, the myPANTONE application for the iPhone failed.

 

VIGC warns users for the inaccurate color rendering of myPANTONE on iPhone

We can quite quickly conclude that this application is unreliable as a color reference tool. PANTONE should have tested this tool thoroughly beforehand. We were able to spot a significant color difference after just one test. PANTONE claims to be a color authority in the industry, so it should know that the screen of the iPhone is not accurate enough to create a visual reference.

This might have consequences for the industry: designers specify colors in PANTONE, which means printers must comply with these colors. So we need a high level of accuracy and reliability. Unfortunately this is not what myPANTONE for the iPhone delivers. In fact, the application could prove to be a liability for the industry. We hope that its use will not result in a law suit, with charges pressed against a printer because the printed job didn’t look like the myPANTONE reference on the iPhone.

PANTONE should thoroughly investigate this. At the launch of PANTONE GOE, the company forgot to specify that the RGB values are sRGB and not AdobeRGB, which is used most frequently in prepress. And now this new iPhone application does not  live up to their claim of being the color authority. Unfortunately, because there is a huge need for reliable color references in the printing industry.

 

Eddy Hagen
managing director and trend watcher VIGC

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