CRI - Colour Rendering Index

Discussion in 'Landscape Lighting' started by INTEGRA Bespoke Lighting, Feb 20, 2008.

  1. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Messages: 4,102

    Wow. I have known about CRI and its importance in lighting for a long time, but I never investigated how it is measured until just now.

    To learn more, click on this link:

    Now if they could only make a hand held meter that would measure it for us!

    Light source CCT (K) CRI
    Clear mercury 6410 17
    High pressure sodium 2100 24
    Coated mercury 3600 49
    Warm white fluorescent 2940 51
    Cool white fluorescent 4230 64
    Deluxe warm white fluorescent 2940 73
    Day light fluorescent 6430 76
    Metal halide 4200 85
    Deluxe cool white fluorescent 4080 89
    Metal halide 5400 93
    Incandescent bulb 3200 100
  2. JoeyD

    JoeyD LawnSite Silver Member
    Messages: 2,933

    The scale I have seen on CRI shows High Pressure Sodium as a 1 and the Sun as a 100. A good halogen lamp should produce between 75 and 85 on the CRI.
  3. John Pletcher

    John Pletcher LawnSite Member
    Messages: 17

    James: I thought you did nothing all day in the cold.
  4. Lite4

    Lite4 LawnSite Gold Member
    Messages: 3,182

    It seems all the electricians around here favor the High Pressure sodium. It sucks, makes everything a dull orange. These guys don't have a flippin clue how to light anything properly. It seems that all they are really useful for is pushing wire through conduit. Wow, I really got myself worked up over this.
  5. NiteTymeIlluminations

    NiteTymeIlluminations LawnSite Senior Member
    Messages: 367

    I'm much rather see HPS than a cold MH anyday. But then again i work somewhere where i am trying to keep things warm and romantic.
  6. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Messages: 4,102

    Wow, you might be the first person I have ever heard say they actually prefer HPS. You know that it has a brutal CRI right? Ever seen a store sign under HPS? How about a restaurant / pub patio or deck that is washed in HPS... you can hardly recognize the food you are eating. About the only thing worse then HPS is LPS (low pressure sodium - those horrible orange things that seem to have all but disappeared thankfully)

    Next time you have a chance, check out the output from a 39W PAR20 MH lamp, or even the low wattage mogul base MH... They acutually produce a very nice light at low wattages. Perfect for commercial, industrial and monumental applications, just be sure to pick fully shielded fixtures.

  7. NiteTymeIlluminations

    NiteTymeIlluminations LawnSite Senior Member
    Messages: 367

    yeah mon I use da crap load of 39 watt metal halides phillips brand only on entrances but we have security lights on the beach entrances and i need warm yellow light, i dont have anything over 2700 kelvin on my resorts, entrances can be bright and white, the beach guests should always be able to sneak away in a corner and remember why they are together and bright white light detract from that...dont you dim your dining room chandelier at dinner?
  8. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Messages: 4,102

    If I want dim / mood / soft / ambient / lighting the last thing I would be using is HID anything! I really only think HID is appropriate for commercial, industrial and civic lighting... If I had the ear of a resort property, I would be ripping and tearing out the HID sources and doing a dramatic overhaul using lots of LV and some point source LV.

    The PAR20 MH lamps are great for uplighting huge trees in urban areas, or for projecting big bright pools of light from above (again in urban areas) but I surely wouldnt be putting them over an entrance or any other location that is close to the ground. We are talking about a lamp that produces 3750 CBCP! (in flood format) Compare that to an FMW that produces 1000 CBCP or a BAB that produces 525 CBCP.

    When you say you are using 39w MH over entrances... what type of fixture to make it look attractive?

  9. NiteTymeIlluminations

    NiteTymeIlluminations LawnSite Senior Member
    Messages: 367

    two posts ago you wanted me to look at the 39 watt hetal halide and now you are telling me you wouldn't use hid anywhere...what gives?

    Low voltage is great no doubt. Try figuring the expense of doing 20 acres of gardens and doing it low voltage in one big swoop using high end control unit, brass fixtures and running absolutely everything in conduit. Then explain to the resort why the control unit (transformers ) failed a year later due to extremely dirty power, 50 hz instead of 60 hz and frequent brown outs.

    This is not Canada or the US.

    We have HID for security, trust me we need it. Ad we are slowing evolving to some low voltage and leds. We test for years before spending a quarter million dollars on stuff.

    Back to the topic though. I'm proud that my engineers think and are changing out the control systems in the HID lights to HPS to warm things up. HPS is about dinner mood lighting is about 2300 kelvin...thats an mr16 dimmed 60% or so...perfect a i going to eat under HPS nope am I going to protect my property line with it until we come up with a better option to appease security mgrs---yup
  10. INTEGRA Bespoke Lighting

    INTEGRA Bespoke Lighting LawnSite Platinum Member
    Messages: 4,102

    ok ok, I can see what you are getting at. As a perimeter security light a low wattage HPS or MH in an appropriate fixture would be effective. I was thinking gardens, patios, decks, pools, and entrances to all the buildings... You were talking about 'entrances' to the property. Text can be such a poor conductor of communications sometimes.

    I would love to get a chance to light a 5 Star resort someday... one with enough budget and interest to do it right. Talk about disneyworld for lighting guys! All the resorts around here are too worried about "non revenue generating expenses" to really do their lighting properly, which is a shame.

    Have a great day.

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