# 2700 Kelvin or 3000 Kelvin Lightbulbs? Which do I use for my LR and PS work?



## Ryan

Before I explain, my question revolves around what's best for my eyes. I can calibrate my monitor.  I bought new LED lightbulbs to try out. There were 2 different Kelvin ratings for both of them. One was 2700 and the other was 3000.  I got the 2700 ones as they were a better deal. 3 in a pack for the price of 2 of the other ones. So I replaced 2 in my den and the light was much warmer than the old ones. I checked and the old ones were 3000 K. Would the warmer bulbs be better for my eyes?


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## clee01l

Natural sunlight (outdoors with no artifical light) is measured at between 5000°K and 6500°K.  This is packaged as "Daylight" bulb. This appears whiter than an incandescent bulb.  Incandescent bulbs are in the range of  2700°K and 3000°K. The incandescent glow is considered to have a reddish or orangish cast.  Normally, you want to avoid artificial light. When incandescent were all we had as a choice, then 2700°K to 3000°K was considered the norm _for indoor_. Many people don't like indoor lighting to be any different from the incandescent glow that they grew up with.  It does not meant that it is the best lighting to work in however. Office environments have been studied and it was determined that the best office lighting for the eyes was natural daylight (6500°K)  Bright LED computer screens affect this environment more than the background lighting.  You don't want the room completely dark lit only by the computer screen and when working with images, you don't want the background light to be artificial or have that 2700°K and 3000°K color temperature.  Sophisticated color monitor devices will measure and tune the computer display and compensate for changes in ambient room lighting, but you should strive for ambient room lighting as close to natural daylight as is possible and always work in LR using a color calibrated monitor.


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## robosolo

Ryan said:


> Before I explain, my question revolves around what's best for my eyes. I can calibrate my monitor.  I bought new LED lightbulbs to try out. There were 2 different Kelvin ratings for both of them. One was 2700 and the other was 3000.  I got the 2700 ones as they were a better deal. 3 in a pack for the price of 2 of the other ones. So I replaced 2 in my den and the light was much warmer than the old ones. I checked and the old ones were 3000 K. Would the warmer bulbs be better for my eyes?



The bulbs you are using for editing environmental light are too warm. I suggest getting some Phillips LED 5000K 1200 luman spotlights and putting them on a rheostat (so that you can control their brightness).


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## RikkFlohr

I use 5000K high CRI (Color Reproduction Index) Fluorescent and Compact Fluorescent bulbs throughout my studio, work area and printing room.


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## phcorrigan

I think you would be better off with 5000k lights. I have been using TCP dimmable 5000K CFL reflector bulbs in ceiling can lights and I have been relatively happy, but even though they came with a two-year warranty, three out of six burned out within the warranty period (the distributor replaced them no questions asked). I am replacing them with Cree 5000K LED reflectors as they burn out. 

One note about color temperature and CRI: to the best of my knowledge the CRI specification refers to perception of color accuracy, not actual color accuracy. No CFLs or LEDs that I know of are truly full spectrum--they all have some degree of drop out at various points, so they all have the ability to affect your image viewing. The TCP CFLs and Cree LEDs both have a CRI of about 80, and for my purposes that has been sufficient.


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## Ryan

Thanks for all the replies, so I'll be looking for brighter bulbs! HD is probably not the place to go for them.


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## phcorrigan

Ryan said:


> Thanks for all the replies, so I'll be looking for brighter bulbs! HD is probably not the place to go for them.



It's not brighter that you want, it's higher color temperature. I buy the 5000K Cree LED bulbs at HD.


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## clee01l

phcorrigan said:


> It's not brighter that you want, it's higher color temperature. I buy the 5000K Cree LED bulbs at HD.


This is correct.  Brightness is expressed on the box measured in Lumens.  In the out dated incandescent technology, this was directly correlated to the power consumption (more watts = brighter light) Some newer technology lights advertise an incandescent watt equivalent because most people do not have a good handle on using luminescence units to measure luminescence (brightness).  Color is measured as a relation to the color of the sun. Its surface temperature is approximately 5778 °K (5505 °C)  This color temperature is considered the color of daylight.


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## phcorrigan

clee01l said:


> Some newer technology lights advertise an incandescent watt equivalent because most people do not have a good handle on using luminescence units to measure luminescence (brightness).



Yes. CFLs and LED lamps will show their incandescent brightness equivalent as something like "65 Watt Equivalent," which means it will put out approximately the same amount of light as a 65 watt incandescent bulb, but use far less power.

By the way, the prices are really dropping on LED lamps. A few months ago I paid about $21 for a Cree dimmable BR30 5000K LED bulb. Now they are under $18 at HD.  Standard 60w equivalent 5000K dimmable LEDs are under $8 each.


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## Ryan

phcorrigan said:


> It's not brighter that you want, it's higher color temperature. I buy the 5000K Cree LED bulbs at HD.


Sorry, that's what I meant. I guess it's a trip to the states then in my future. Everything online points to really expensive..like about $69 each.


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## phcorrigan

Ryan said:


> Sorry, that's what I meant. I guess it's a trip to the states then in my future. Everything online points to really expensive..like about $69 each.



I suspect those online prices are for multiples, such as 4-packs or 6-packs.


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## LouieSherwin

Hi, 

Keep in mind that the viewing environment has a huge effect on your perception of color. In a dark environment, like a museum, your eye will perceive a 3500K lamp as looking like full sun. If you put a 5500K lamp in the same environment you would see is as way too blue. Second keep in mind that the marketing term "full spectrum" only means that the bulb in question "covers" the full visible spectrum but does not necessarily tell you how accurately it does so. The color rendition index (CRI) is a helpful guide that tells you how complete the bulb is in the output spectrum. Anything less than 90+ CRI will probably not be accurate enough to proof prints.

Although much better than even a year ago most of the consumer LED lights out there are going to be deficient in the red area of the spectrum, even though they claim "full spectrum" there are holes in the red output. I saw this recently when testing a number of different lamps to replace the quartz par20 lamps in the gallery where I am a member. The best LED we found was from Soraa (www.soraa.com) not cheap. When A/B testing any other LED bulb v.s. the Soraa bulb on various artwork you could easily see loss definition in any area of deep red tones. 

As an alternative you can get what I consider the gold standard of full spectrum incandescent bulbs for Solux.net. I have been using their 4700K MR16 bulbs as my critical print proofing light box. These bulbs are used world wide by the many museums because of the extremely high quality in color rendition and very low UV output.

For critical color work I highly recommend either of these. 

-louie


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## sizzlingbadger

Cheapest option is to switch the lights off


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