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Studio lightning - spiral bulbs

I would like to ask you abour studio lightning. Are two 30 W spriral bulbs enough to light up painting area?



  • Datura

    At 800 lumens five foot from your canvas will produce about 32 lumens as a detailed work light.
    Architects specify about 1000 lumens. You should aim for at least 800 on your work surfaces.
    Important requirement if you need to do sustained and repetitive color matching.

    So you will need 15000 lumens on your ceiling to arrive at 900 on your canvas.
    It’s cruel but that’s the way the inverse square law of light works.

    Suggest you shop around for 5000k LED Battens, three 40 watt units should do it. DIY plug ins are available.


  • DaturaDatura -
    edited January 9
    Wow Dencal, this is so helpful! I knew that I have to look for 5000 k bulbs with high CRI, but I was unsure about the strenght od the light. You helped me a lot! 
  • Hello @Datura, I have 1x bulb - 1500lm, 6000K and 1x bulb 1500lm 4500K in my studio on my ceiling (aproxim. 1-2m from work surface) Pover of the bulb (Watts - W) reflects the efficiency of light bulbs, not it´s light intensity.
    My light condicions are not ideal as I can see thanks @dencal´s calculation .. especially in dark color tones is very difficult to distinguish individual color shades (gray-dark blue mixing).
    So @dencal, in my case - I need also aprox. 15000lm on my ceiling .. Does it mean I need 10x this light bulb instead of 2x ?
    Don´t know how solve this problem  ... propably will have to add some type of external reflector (have no
    other socket for light bulbs on my ceiling :(
  • Marik

    Trust the manufacturer’s rating for light output regardless of the type of fixture.

    So let’s start with 900 lumens on the canvas as the target.

    At one meter you will need to put 9900 lumens on the ceiling, that is three (40 watt), 3600 lumen LED battens.

    At two meters you will need to put 30000 lumens on the ceiling, that is eight (40 watt), 3600 lumen LED battens. Which seems excessive and expensive. Let’s try 750 lumens on the canvas at two metres.
    Need 24750 lumens or six, 3600 lumen LED battens. Just a thought at two metres a 35 degree angle will be difficult to achieve. Remember you can raise the easel too. Centre of the canvas at eye level and use a high rise chair/stool.


  • Inverse law? Sounds like something Murphy made up. I have one 85 watt CFL curly bulb. At seven feet, it is bright enough to distinguish all colors and nuances of shading. However, the cfl bulbs will dim gradually with continued use and the color (5000K) will shift to a lower range as well. so I will follow your suggestion, @dencal , in the future. I also have a fixture and some dimmable led bulbs to build @MikeDerby's design but have not had space or time to build the stand and put it all together. I hope the salesman at home depot knows what a batten is.
  • MarikMarik -
    edited January 9
    thanks for comments @dencal -
    I looked on the internet and studied lighting issues a little bit.
    Well - the most relevant unit for intensity of light hitting a surface is Lux - and 1Lux is equivalent to 1lumen per squere meter.
    Day light has wide range of intensity 150-100 000Lux .. but for reading and drawing by arteficial light is 750Lux good enough. ... but ?
    I readed this :
    "More than 500 lux – If you have an area where intricate work is being carried out, then very high lux values may be needed. Where fine detailed work is being carried out, anything up to 2,000 lux can be used – this is usually only necessary in fairly unusual circumstances. For most purposes, 500 lux will be ample. "
    If I have light source and surface in 2m distance from the source - I can calculate : for example - light bulb 5000lm - lighted surface 4m2 (distance 2m) by 1250Lux.
    I think that very important for calculation is also space of the room - reflectance of the surfaces .. how many light reflects to my eye and so on .. not so easy to calculate. Human eye can adapt very well on light conditions ...
    Thanks a lot for this conversation and sugestions !

     My light situation is this:

    The angle is suitable - no glare ... but as you can see - because of big format, the surface is not equally illuminated.
    My conclusion for now:  I will strengthen my light source - ecolight led 5000K 30Watt or 50Watt 2x .. (4800lm or 8100lm) (now I have only 3000lm and I can live with it)
    I definitely expect an improvement .. and hopefuly comfortable enough.

    I found interesting source for calculating light intensity ... write more later .. :)

  • BOB73

    Looks like Home Depot use the term “Linear” to describe LED Battens.


  • Marik
    Thanks. Yes it is important to give careful consideration to studio lighting.
    I think raising the easel is the best improvement you can make.
    Another option is to lower the light units by suspending them in a box or on a chain.
    There are apps to use on a smart phone or iPad to measure the light falling on your palette and canvas.

  • I founded this link:

    Lux - lm depending on angle and distance.
    If I put 5000lm bulb - 135° angle and 1,6m distance I have 504Lux ... so I try this way 

    Thank you @dencal for the hint about apps in smartphone and level of easel .. 
  • I'm not sure how accurate they are, but you can get free luxemeter apps for your phone. I just installed this: to try. You just hold it up and it tells you the lux at that point in the room. Mine reads about 500 where my canvas is, and I find my natural light LED bulb quite powerful... might be worth trying. This is the bulb I ended up buying:

    I originally bought one of those curly florescent bulbs but was concerned about breaking it accidentally with the mercury content inside, so replaced with LED. This is a useful article:

    and this is quite a useful video:

    In the end, I spent four quid on that bulb and moved on with my life hahahaha.
  • CJDCJD -
    edited January 10
    I use 2 85 watters of the kind mark recommends. The giant spiral white ones. I imagine my studio is about as bright as his. Got the lights on amazon

    In regard to tischlers advice- if youre painting from photos then you want a bright studio light.. Not a darker one. Painting from dimly lit photos will give you a dark painting in normal light
  • CJD said:
    I use 2 85 watters of the kind mark recommends. The giant spiral white ones. I imagine my studio is about as bright as his. Got the lights on amazon

    In regard to tischlers advice- if youre painting from photos then you want a bright studio light.. Not a darker one. Painting from dimly lit photos will give you a dark painting in normal light
    Thanks @CJD for your comment - I agree, this is very good point, but .. what is " normal" light ? ... It depends on where the painting supposed to be (hang) .. Have the Galleries so bright lighting ? Or et home ... 

    I defenetly thing that more light intensity is better than less .. and crucial is temperature.

    I ordered 2x big light bulbs 5000K, (2x 5000lm) .. and hope this brings me optimal light conditions.
    When it wil be too much I can put on sunglasses  B)

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