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Light bulb enquiry: How many lumens of light should you aim for when buying a 5000K bulb?

Hi,

I am setting up an easel and lighting as per Mark Carder's instructions. He suggests using a 5000K LED spiral bulb. 

I can find 5000k bulbs fairly easily where I live (NZ) but there is one variable I am unsure of, when buying a light bulb.

How many lumens of light should you aim for when buying a 5000K bulb?

My local hardware store sells 5000K LED bulbs, but have a misley 350 lumen output.

Any advice would be much appreciated. 


Comments

  • dencaldencal -
    edited March 20
    geoffrey_38

    The height of your ceiling and reflectivity of your walls ceding and floor are factors to consider.
    The ceiling to the centre of the easel is the determining factor.

    Attached elbow is a screen shot of my worksheet for studio lights. This matrix is based on the inverse square law of light.

    Aim for between 800 and 1000 lumens on the canvas. Highlighted in yellow.
    So at four feet, light to canvas, you will need 14 to 16k lumens on the ceiling.
    Three high output led tube fixtures should do the trick.



    As a general guide 350 lumens is an average desk lamp. Architects recommend 1000 lumens for detailed and sustained discrimination at a workspace.

    Denis
    geoffrey_38
  • dencal said:
    geoffrey_38

    The height of your ceiling and reflectivity of your walls ceding and floor are factors to consider.
    The ceiling to the centre of the easel is the determining factor.

    Attached elbow is a screen shot of my worksheet for studio lights. This matrix is based on the inverse square law of light.

    Aim for between 800 and 1000 lumens on the canvas. Highlighted in yellow.
    So at four feet, light to canvas, you will need 14 to 16k lumens on the ceiling.
    Three high output led tube fixtures should do the trick.



    As a general guide 350 lumens is an average desk lamp. Architects recommend 1000 lumens for detailed and sustained discrimination at a workspace.

    Denis

    Thanks!

    A great worksheet. I knew the community would pull through with an answer.

    Cheers,
    Geoff
  • dencaldencal -
    edited March 20
    geoffrey_38


    Mark has a good design comprising six lamps such as those you have available locally.  This unit should output about 9000 lumens.  Here is a pic.



    Here is a link to the video; 


    Denis



  • great question and some awesome answers
  • So I found a supplier of the bulb which Mark uses in his diagram for a small studio. Shop at photography shops for this bulb.
    Here is a link to the bulb, for New Zealand residents. Although I am sure they would delivery internationally.

    https://www.photoshack.co.nz/product/1312-Fluorescent-Bulb-5500K
  • geoffrey_38

    Opt for LED where possible. Fluoro has a pretty messy and uneven light spectrum emission. Also contains mercury and arsenic. Fluoro has a much shorter lifespan compared to led.

    Denis


  • edited March 21
    dencal said:
    geoffrey_38

    Opt for LED where possible. Fluoro has a pretty messy and uneven light spectrum emission. Also contains mercury and arsenic. Fluoro has a much shorter lifespan compared to led.

    Denis


    I agree Dencal however, for my purposes this bulb is fine. If I want to bump up the lumens I could install two or buy the 150W version. But for my purposes 5000 lumens will suffice. For now :)  

    This is what Will Kemp https://willkempartschool.com/ states about setting up a small studio with this bulb:
    (note: this is the same bulb Mark uses in his 'how to set up a studio' video https://www.youtube.com/watch?v=KMOSvmdFKY4 ) The bulb is for high quality professional photography.

    My top tip for lighting a small art studio with a ceiling height of 8 – 10 foot, is a bulb you can just screw into your existing fitting and is a Compact Fluorescent Bulb.

    It should have a 90+ CRI rating, 5000K- 5500K colour temperature and around 85 watts, it will give a light output of around 5000 lumens at the lamps source and will give you a bright, clean light to work under.

    Pro Tip: The light strength diminishes as the light is moved further from the source so by the time it hits your canvas it would probably be a 2/3 of the strength, around 1,800 lux – based on you sitting 1.5 meters away from the lamp in the ceiling.

    The recommended lux level for detailed drawing work or very detailed mechanical work is 1500 – 2000 lux so this would fit the bill! Hurray!

    However, 1500 lux is still very bright and I would imagine for most home studio situations, this bulb would give out ample illumination.

    For many classical paintings, a lux level of 250 – 450 lux can still work very well, especially if your finished piece is going to be hanging in a darker space.

    The lux value changes depending on how far away from the source you are painting, the angle of the beam etc.. but this lux calculator is very handy if you want to check your own studio and find a light level that works best for the style of work and type of paintings you are going to be creating.

  • geoffrey_38

    Good to see you have a solution. Onward and upward.

    Denis


    geoffrey_38
  • For close and detailed work, if it looks way-too-bright you're getting close.

    You can always unscrew one-bulb or turn it off later, the the human eye is so sensitive that it can fool you.
    dencal
  • I mounted two Hyperikon outdoor LED flood lights (5000K, 4000 lumens each, 110V, with cords but no plugs, from Amazon: out of stock currently, made in China)  on a 24" aluminum T-bar attached to the end of a 48" steel shelf standard (with a counterweight on the other end) mounted at its middle atop a photographic light stand:

    dencal
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