Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

You can send an email to [email protected] if you have questions about how to use this forum.

A few beginner studio lighting questions.

Hi all,

If you have a CRI of around of around 94 as your studio light but a CRI of only around 82 on your still life setup will this lead to any problems?

For my still life lighting I'm struggling to find high CRI (90+) bulbs that are dimmable so would it be preferable to just aim for high luminosity bulbs with a high CRI that are non-dimmable and then just use different fabrics/materials to adjust the brightness and balance with the studio lighting.

I should perhaps have gone with strip lighting for the studio but I have already made an LED fixture - based on the fixture in one of Mark's more recent videos - which I attached to a TV mount ceiling bracket (see below).

I have recently found what look to be great LEDs for the studio light which would replace the current 5000k/2000l/CRI>80 bulbs pictured in the current setup as they have great all round specs; 3300/5500/6600 lumens, 5500k, CRI>94. Below is a link for anyone interested.

https://luxlight.shop/collections/spring-cushion-stand/products/vivid-pro-5500-lumen-led-bulb-94-cri-5500k-daylight-balanced

My studio lights are mounted such that the bulbs are about 4ft from the eye level of the easel (although it could be lowered slightly) and thanks to the chart I've seen generously provided by Dencal in other posts, I could see I needed a minimum of 14,000 (7 x 2000) lumens from the main light. This meant compromising the CRI values but these bulbs I've just found would address that.

For the still life setup, I currently have a good ol' painted bucket with a mounted E27 fixture holding 5 LED bulbs which are a mix of 1500 and 900 lumens. These are CRI 82 as an average but I'm just wondering what  difference it would make to have all lighting at CRI 90+.

Any advice would be much appreciated. I'm hoping to get the lighting sorted and not have to think about it again (famous last words!).

Many thanks from the UK.


Comments

  • You may be overthinking this. I did most of my illustration work for 25 years with a 'daylight fluorescent ' desk lamp. Hundreds of drawings and paintings. I painted watercolors  for another 15 years with the addition of another table lamp. Everything looks great reproduced without issue. 

    Now I use a couple of these for stand up painting. High CRI. Variable degree K I paint at 5200k. Mine are older not as fancy. Cheap and portable. I still use my 53 year old desk lamp for painting at my drawing board. Same bulbs since 1968.

    https://www.amazon.com/Video-GVM-Lighting-Photography-Portrait/dp/B08G8HCYFW/ref=sr_1_22_sspa?dchild=1&keywords=gvm+led&qid=1615408244&sr=8-22-spons&psc=1&smid=A29PNJE82TLM1V&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyV0RMRTNNSTROQ1lEJmVuY3J5cHRlZElkPUEwNDM3NzU0M1RHNkpZVEJINTdHSyZlbmNyeXB0ZWRBZElkPUEwOTcyMTkzMzA5UklaUk5SMjQ0WiZ3aWRnZXROYW1lPXNwX2J0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
    phoria01
  • dencaldencal -
    edited March 11
    phoria01
    If you have a CRI of around of around 94 as your studio light but a CRI of only around 82 on your still life setup will this lead to any problems?
    It would be ideal to have these parameters matched, but the difference here is marginal and unlikely to make a significant difference. Yes, your mixed values will be slightly less saturated than reality, but the coherence and value relativity will look fine.

    The difference here is illustrated in the two middle apples



    My concern is the strength of your still life lights at 6000 lumens. Depending on your shadow box setup, this may be too bright to control. Caution is advised as dimmers may alter colour temperature and colour rendering index of the light source.

    Denis

    phoria01
  • @Kingston I think you're right, I'm over valuing that 8-10 CRI especially when we're talking potentially expensive bulbs.
  • @dencal That's a useful diagram for some context. Based on what you've both said regarding the CRI I'm happy to leave things as they are for now...perhaps something to worry about once I've done a little more in the way of paintings i.e. any at all.

    That's interesting that dimmers can alter the colour temperature and CRI. The obstacle I keep running into regarding luminosity is if I'm starting from the lumens at the canvas - aiming ideally for around 840-1000 - then I need high lumens at still life. 

    So I guess my question is do you think it's worth sacrificing lumens at the canvas for a greater range of lighting manipulation at the still life?

    Many thanks.
  • phoria01

    No. Keep your studio at that brightness level. Your eyes need light and lots of it for fine and sustained value discrimination.

    Use that still life cluster and aim for a good white balance and proportionate strength relationship.
    Unscrew some of the bulbs, start with two. Use a shadow box variable aperture with some white plastic removable filters. This should allow plenty of scope to vary up or down as the test results indicate.

    Denis
    phoria01Dustin_Cropsboy
  • @phoria01
    Consider this. The inside of your shadowbox can be any color you want. You may want a mood. Use a color gel filter over your light. Any color. CRI in the box is irrelevant in my mind. On your canvas it's important. The inside of the shadow box is a stage in the theater of your imagination. Sometimes is an early morning light falling on a piece of fruit. Next week it's a moonlit scene of a steaming cup of cocoa with a hovering bumblebee. 
    phoria01GTO
  • I've just setup the still life light with the 3 x 1521lm and 2 x 900lm (6363lm) and the value is still slightly  under that at the easel. Only when I remove one of the studio bulbs do the values match.

     It seems the only options are to go for 4/5 x 1521lm at the still life or lose 1 bulbs worth of luminosity at the canvas! Problems arise either way.
  • phoria01

    If you can get a white paint balance at 4 x 1521 then your done.

    Denis
  • @Kingston Thanks for that, it's helped make much more sense. I thought this was perhaps the case because I'd never seen anyone (such as yourself or dencal) advising along the lines of CRI with respect to the still life. 

    It's just the value matching which is the only problem left now then I can dive into this.
  • @dencal @Kingston That's great, thank you both for your help.
  • @KingstonFineArt comment about the shadow box being the theater of the imagination is interesting.  In the past I struggled with getting the white color checker to balance with the white in the box.  In the last painting I did, the lighting in the box was so low that there was no way to get that to match and still have enough studio light to work with.  
    I have also used a warmer setting of the light in the box because I like that warmer color for the mood.  
    I will add one more observation.  I have also changed the color from what is in the box for an object or surface because I thought it looked better in the painting.  (In the last painting the table was actually bluer but I wanted it more gray. )
    When I was “learning DMP” (do we ever really stop learning?) I followed everything to the letter.  The level of realism can be striking in that case.  But sometimes straying from reality is necessary (better...who knows?)
    phoria01
  • @GTO Interesting, was it just the last painting you did without balancing the whites?

    Playing with warmer/cooler palettes and changing the fundamental colours of your subjects sound like great skills to harness. 

    Did you set yourself a certain number of paintings to do to the letter before finding your own way a little more? I'm setting myself the target of 5 but I imagine it's going to require a lot of discipline to get to that point.
  • Temperature is simply a relativity thing. Like color and value. Cad Red Light is warmer than Cad Red Deep. Yellow Orange is hotter than Cad Red Light. Ultramarine is warmer than Cobalt Blue.

    Light is the major factor here. The morning light is warmer then evening light. Midday Light is much cooler than either. The are light meter sapped where you can measure color temp in degrees Kelvin. 

    Mostly it's learning to see.Seeing with a full understanding of the color of light. How the color spectrum, color wheel, works. Seeing with a purpose. 
    phoria01
Sign In or Register to comment.