accurate colour

[HughGilbert]

Hullo All,

I'm trying to reproduce someone's watercolour painting...well half a dozen of them. 

The watercolour is a lemon yellow predominately.  I cannot get the yellow to reproduce... it comes out orangey.

Any thoughts anyone.  I'm using Kodak colour swatches and greys are nicely neutralised but the colours are all over the place....

Oh yes and I'm having a similar problem with some pink silk that is emerging on my screen as red!

Help

No drink today because its Lent...(got to show who is captain of the ship sometimes!)



All best


Hugh

[NickT]

Hello Hugh
Assuming your monitor is accurate... Have you tried shooting in reproduction mode? Failing that pick the colour(s) in the colour wheel and tweak them to suit.
Nick-T

[David Grover]

Also Kodak grey patches are not known for their neutrality!

[mauro risch]

I use the Macbeth color checker to find the neutral grey.

[Dustbak]

Make sure you have a really neutral grey patch. I have found that there are grey cards that are way off either (mostly) too blue making your images too yellow (resulting in the assumption of a color temp too high) or cards that are too yellow resulting in the opposite.

Using reproduction mode can help somewhat, however I have not had really lots of better results with that. Most of the time it simply generates an image a lot 'flatter' but with similar colors.

I have sometimes similar problems with clothing/garments. Not only sometimes the color is off a bit which is fairly easy to correct via PS but many times I need to re-color items. Some items I just get the Pantone color, others a small sample of cloth. What way of correcting do others use? I use HSB lots of time which I find the easiest way to get to a certain color fastest.

You open you image in PS. Make a hue/sat adjustment layer, select the color range you want to adjust and start with finding the hue that comes closest to what you need. find the saturation and lightness and in most cases you will get close enough.

If you can get a color number or patch you can also convert your image into B&W by means of a B&W adjustment layer, put a solid color adjustment layer on top of your B&W layer with the sampled (or numbered color) and put it on blend mode 'color' this will render you whole image that color in various tonalities. Make a group of the 2 layers and put a black mask on top of that. You now can paint in the right color with a white brush (paint in the mask). If you are off with tonality you can also put a levels adjustment layer in between the B&W en solid color layer to get to the right tonality.

I am looking into ways of making this stuff even faster. Is anyone using the Colormunki to scan surfaces to get to the right color? If so how are your experiences with this? Before buying one myself and being the guinea pig I figured I might just as well ask if anyone has gone this route before me

BTW, as Nick mentioned you can also tweak the color in Phocus however I still need to find out if that generates better results than PS and if so, why?

[HughGilbert]

Thanks guys...

David... I'e been suspicious of the Kodak cards for a while...permanently on repro mode...

Nick Dunmur put me on to a Grey card made in the states... its plastic... I use that a lot.  I also use the Gretag card. 

Dustbak thank you for the suggestion...

I think it is time for more testing.

ND suggested that I should buy my way into a Camera Input Profile from <http://www.basiccolor.de/english/index_E.htm>  I spoke with them after speaking with Nick and they said that their input profilewouldbe good... Well they would wouldn't they... They sounded confident though...

One of our group does a lot of repro work in the US, can anyone remember who he is?


All best


Hugh

Sunny in London...

[Dustbak]

I have been looking for input profiling since my Leaf backs several years ago but never actually did it. It isn't particularly cheap and since the chain after me can be really large with all sorts of parties that can screw it up I always ended up not doing it.

I would like to know from people that did go that route, how their experiences with it are. I almost bought the Gretag camera profiling solution, it seems the German party delivers similar functionality. What are the costs of this? (like the Gretag around 2,5K euros?)

I guess you can now use the input profile in Phocus.

I still am not really convinced of the practical benefit of solutions like this. I am sure it will work but will it be worth it? Sure would like to hear some opinions on this.

I have heard too many times, 'Yuk, your images are much too blue. Only to find out people were judging on a beaten up office monitor which wasn't even calibrated'. After my remark they should use a better monitor and at least calibrate it, I got back. 'Our clients look at it like this, so it must look good here, only a very small percentage of people look at good screens'.

In print it looks great and very rarely I am off but since a large part of what I do is also used on screens it does get kind of blurry so to speak.

[NickT]

I think there's merit in the idea of custom input profiles in say a fine art copy situation. In that situation you are profiling your back's response to the setup (lighting) and if that setup remains the same then the profile should be useful. Move a light however, or go to a different setup and the profile is useless, you will be better off with the mapping (of colours) that Hasselblad have done.
Nick-T

[Dustbak]

I believe it is only usefull as long as you can have total control from input to output and even can control the circumstances in which your output is being watched (and if you really want to be anal about it, the eyes that watch it) and have every step profiled (or deal with other people that do and know what they are doing).

Is anyone using the profiling tool of Adobe?   

[HughGilbert]

The difficulty with obtaining accurate colour using the grey card is that the Hasselblad 'Golden Shot' is great for most shooting.  In the business of reproduction photography, fine art needs a degree of subtle accuracy that is difficult to achieve.

My quest for elusive accurate colour is driven by the apparent crossed curves (remember film) that you can get when balancing with a grey card.

Next week I'm going to polish everything and have a last try with the gear I have before pushing on in the direction of an input profile....

If anyone has been there ahead of me please let me know...

All best


Hugh

off to Antwerp on Friday for a weekend of kulture...Have a good weekend all

[Phil G]

Not sure if I have taken the correct route now we are all expected to be multi skilled I prefer to let someone else more experienced do the printing I just want to give them the best file to work with.

Like you Hugh I have a stack of paintings clogging up my studio Watercolours,  Oils and Acrylic all framed! which I need to shoot over the next few weeks.
I was going to take this as an opportunity to 'calibrate' and evolve a protocol for the archive work on documents many from 17th ctry which I am more interested in capturing and was the reason for buying the H3D39 in the first place.

The ColourMunki appears to be a neat piece of kit I bought one and gave it to guys who do the printing to calibrate their end and then come and do mine.  Also with the colormunki you can take point reading directly off the object or painting.

In an attempt to keep it simple I intended to use a GMacbeth target and a couple of Elinchroms, set the Blad on ? Flash, thinking of using the 210mm to try to standardise and give  some room to get at the art work. and see how it goes.


And after all this someone will put it in an orange frame to match their decor and use florescent lighting.

Phil

BTW if you take out a new sub to the BJP you get £100 off the Colormunki bring the price down to just over £200!
http://www.bjp-online.com/public/showPage.html?page=bjp_subscribe

Correction: GMacbeth I mean Munsell ColourChecker

[GrantRH]

Hi Hugh

I read with interest your dilemmas in your quest for capture of subtle colour renderings of paintings etc. I have been shooting artworks for high quality repro for many years now both film and digital now since the days of the Imacon 3020 digital back, currently with a HD3II-39MS.
Capturing accurate colour with either Flexcolor or Phocus can be difficult but you certainly need to be in Reproduction mode. In this set-up you have to watch exposure carefully and even tweek some colours. This needs to be done whilst viewing the artwork within a colour controlled environment to match the monitor colour temp. With the latest Phocus version you can use a custom input profile within the Reproduction mode. Have not tried this yet as getting an accurate input profile is difficult and probably requires profiling a number of iterations of the same set-up and averaging the results. As NickT said earlier a custom profile will probably only be precise for the profiled set-up especially considering the subtlety of colour you are expecting to capture.
Whilst colour can be a difficult component to capture I have been giving considerable effort in getting the tonal range accurate. i do not feel it is enough to use a flat curve as Reproduction Mode employs so I have created custom tone curves based on different set-ups. Changing the tonal range does change the colour rendering saturation.
I have tracked down many of the papers written by art museums and the like and whilst these issues are muted upon no solutions seem to come forward.
It appears these institutions get it as close as possible at capture and then tweek the file for print based upon proofing for the output device.

Oh and by the way I have had success with the White Calibration tool for creating even colour across the capture area.

Let me know how you fare

Grant

[Alastair Bird]

I have heard of studio strobes spilling a lot of UV and having them interfere with accurate colour.  Have you tried the Lee 226 UV filtration (or the Rosco equivalent) over your lights, if you're using strobes? Or have you tried the same shot with Tungsten or Kino lights to see if it's a camera issue or a lighting issue?

Just throwing out ideas...

[Phil G]

Grant Quote "I have tracked down many of the papers written by art museums and the like and whilst these issues are muted upon no solutions seem to come forward.
It appears these institutions get it as close as possible at capture and then tweek the file for print based upon proofing for the output device."

Grant I would appreciate any links you might be willing to share can you Email or PM me

Having just spent the day in one of the major institutions I found that the use of KODAK colour and grey scale patches  * down the side of the document painting etc... is still the current practice.

We are thinking of using the Munsell Color target as a standard for 'calibration' but I am at the bottom of the learning curve on this and need to do a great deal deal more research. 

and to pick up on Alastair's suggestion

In my pre-digital days it was a couple of Tungsten security lights in sheet metal hoods with Rosco filters helped to keep the studio warm on winter days.

But then again do you need full spectrum illumination?? and are you trying to use the camera as a photo-spectrometer and how do Multishot backs differ from single shot on the colour issue???

Phil

* they are now called Tiffen Greyscale and Colour Separation Guide Q13 (8") and larger Q14 (14")

[HughGilbert]

As a matter of interest, I have been photographing artists work for a number of years. 

THe key issue that I have is apart from the occasional 'misting' to magenta, when I neutralise to a known grey card (not the kodak ones, although I leave them in the frame for others to reference to if necessary) the colours in the image I am photographing meander off just a little to places that I know are not quite right.  Lemon yellow is difficult and always warms up.  It's a bit like crossed curves in film.  And throughout all this the grey card remains spot on!

I always cross polarise and always, since digital, use the 'reproduction mode'.  My studio is set up for the work.  I have the floor marked out and the lights have exact places to sit depending on how large the piece is.  Concrete floor... studio stand and tape measure at the ready and a sturdy artists easel to hold the art piece.  Flash units are Profoto D4 units. 

I too have done a lot of research, from time to time, and never found anything sensible from any of the museums.  Although I noted last weekend that the Antwerp Art Museum was using a Metz flash unit and a couple of small soft boxes...

Apparently a major art photo house in London uses tungsten. (I find it hard to believe).  I was at Cirrolite last week and they suggested that I try a Kinoflo; apparently the kinoflos are used by a lot of art repair studios.  However Cirrolite said that the gas in digital flash units gives a remarkably uniform spectral coverage.

The cost of Accurate Colour, ie an input profile which you can put into Flex or Phocus is not cheap.  Dcam is about 950 Euros.  Gretag Macbeth is about 540 GBP.  Others are between in price.

So the search goes on (I have to say that I have had some good advice from a fellow user in the midlands for which thanks)...

There is a fellow Flexframer in the US who photographs art...I cannot remember his name at the moment.  If he knows who he is, perhaps he might like to contribute to this thread...

All best

Raw with puffy clouds and sometimes wet today in London


Hugh