Retail research

LEDs are increasingly being used for retail applications, but how do shoppers respond when their coveted products are bathed in solid state light? The answer may lie in a study recently commissioned by Xicato. Andy Pearson reports

Has LED technology reached the point where it is set to take the retail industry by storm? The answer is important because LEDs are more energy efficient and have a longer life than the halogen lamps traditionally used to light product displays. Yet, despite LED’s obvious advantages, retailers have been reluctant to make the switch from halogen. One reason for their reticence is the perception that LEDs struggle to render reds, browns and other warm colours effectively, so the merchandise fails to grab shoppers’ attention and sales suffer accordingly.

LED manufacturer Xicato wanted to find out if there was a basis for the retailers’ fears. It commissioned lighting application researcher Colette Knight to evaluate the effect of light quality on the attractiveness of merchandise and Peter Raynham, lighting education trust lecturer at University College London, to review the research.

Location, location

Knight chose the Pied a Terre ladies’ shoe display, in the House of Fraser department store in London’s Oxford Street as the test location. A display with three identical alcoves was installed. In addition to two halogen spotlights, each alcove was fitted with two types of LED spotlights: Xicato’s Standard LED spot, with a colour rendering index (CRI) of Ra 80, and Xicato’s Artist Series LED. The Artist Series has a CRI of Ra95 and was developed specifically to render deep reds (known as the R9 reference sample) in a similar way to halogen. The shoe display included a pair of red shoes.

Nineteen dedicated shoe-shoppers were recruited; each was interviewed at a scheduled time by professional interviewers. The research was divided into two parts. In the first part, the accent lighting in all three alcoves was provided by either halogen, Standard Series LEDs or Artist Series LEDs. The respondents scored the result based on how effective the display was at grabbing their attention. In the second part, each alcove was illuminated by a different lamp to enable respondents to make a direct, side-by-side comparison of the lamps on each display. To ensure a realistic set-up, no attempt was made to isolate the display from the ambient lighting. “In addition to hardcore shoe shoppers, 31 lighting specialists from firms such as Light Bureau, LAPD, and Light Projects, were also interviewed to get a professional view on the effectiveness of each lamp type.”

Colour me beautiful

The experiment concentrated on making colour rendering the only variable. However, the designers felt two other variables came into the mix. Firstly the beige colour of the display background was said to be more bluish under the Artist Series LEDs. However, since no other background colours were tested it is difficult to quantify what impact this had on the responses. Secondly, the light sources were clustered in two triangular formations above each alcove and, as a result, the halogen lamps were positioned further from the back wall than the LEDs which affected their beam spread. Again, because the test was not carried out with the halogen in a different position it is also difficult to quantify the impact of this variable on the outcome.

So did light quality have an impact on the attractiveness of the merchandise? In the first part of the test, shoppers were asked to look at the red shoes on display and to evaluate how the colour appeared to them under sequential lighting scenarios. Although the halogen solution was rated slightly better than the Artist Series LED, the report states that there was “no statistically significant difference” between how the reds appeared under halogen and under the Artist Series.

However, in the side-by-side comparison halogen was the clear favourite. One shopper was quoted as saying: “It makes the shoe stand out more than the others, especially from a distance”. This suggests that if halogen lamps are to be replaced by LEDs with a similar CRI then it might be better to change all of the lamps in a display rather than piecemeal.

Unsurprisingly, red-coloured shoes were perceived to be less vibrant for the Standard Series LEDs under both the sequential test and the side-by-side test. One shoe-obsessor commented: “Too bad – these are nice red shoes. They deserve better lighting”.

The same but different

The same lighting scenarios were used to gauge the lighting designers’ perceptions of the different lamps. “When we did the test with specifiers, they were allowed to move any shoe they wanted from the concession area and place it temporarily in the alcoves so that they could directly evaluate and compare the vibrancy and attractiveness of the colour under the three different light sources so specifiers also compared shoes of various colours and textures,” says Knight. This added another variable, since designers could have made an evaluation on blue, green or gold shoes rather than just focusing on red.

However the results for the designers’ preferences for the sequential presentations were the same as for the shoppers, with a preference for halogen. Significantly, the difference in performance between the different lamp types was less marked. The report states: “Even though on average halogen scored the highest, there was statistically no significant difference between the scores given the display lit with halogen compared to the Artist Series”. It also states that there was “no statistically significant difference between the scores specifiers gave to the display lit with the Artist Series or Standard Series LEDs”.

In the results of the side-by-side comparisons halogen came out a clear favourite, with 23 out of 31 specifiers preferring the halogen display. The Artist Series was a clear second; 22 out of 31 designers chose the display lit with Artist Series LEDs as their second choice.

The report suggests that some designers’ perceptions may have been influenced by the blueish appearance of beige back panel under the Artist Series. It states: “Some specifiers felt that the CCT [Correlated Colour Temperature] of the Artist Series modules installed in this test was too cool (based on the appearance of the beige back panel) and they took this into consideration in their evaluations of the Artist Series.” This may explain why 13 out of 31 specifiers preferred the Standard over the Artist Series LED.

The real data from this test is still to come, however. Each week the alcoves are lit by one of the three lamp types and sales in the test area are being logged. As a result, rather than a shopper’s perception, the store will have actual sales data to verify whether there really is a correlation between shoes sold and the performance of the lighting. Watch this space…

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