WetCanvas
Home Member Services Content Areas Tools Info Center WC Partners Shop Help
Channels:
Search for:
in:

Welcome to the WetCanvas forums. You are currently viewing our boards as a guest which gives you limited access to view most discussions, articles and access our other FREE features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload your own photos and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please visit our help center.

Go Back   WetCanvas > The Learning Center > Color Theory and Mixing
User Name
Password
Register Mark Forums Read

Salute to our Partners
WC! Sponsors

Our Sponsors
Reply  
 
Thread Tools Display Modes
  #1   Report Bad Post  
Old 08-27-2018, 03:45 PM
Burntpadua Burntpadua is offline
New Member
 
Join Date: Aug 2018
Posts: 11
 
Same single pigment different values: How?

I've noticed that in some brands of paint that they'll have two colors, each of which has the same single pigment but one of which is lighter than the other. For example both Liquitex Basics Primary Blue, lighter, and Phthalo Blue, darker, list PB15:3 as the only pigment. (Unlike, for comparison, Basics Medium Magenta and Quinacridone Magenta which both have PR122 as the color pigment, but the Medium Magenta also has Titanium White added, which explains its lighter value.) How do they change the lightness when no second pigment is listed?
Reply With Quote
  #2   Report Bad Post  
Old 08-27-2018, 06:16 PM
Delofasht's Avatar
Delofasht Delofasht is online now
A WetCanvas! Patron Saint
Town of George, Kentucky
 
Join Date: Jan 2004
Posts: 3,344
 
Hails from United States
Re: Same single pigment different values: How?

Variation in pigments can be done through a number of methods during the creation of the pigment itself. The number coding is just a generalization of it's chemical composition many of it's various properties, usually hue. The exact hue will vary greatly depending on the way the pigment is created, and some manufacturers have a number of hues of the same pigment.

Lansco is a pigment manufacturer, they have hundreds of pigments, and some of those have a dozen or more variants of the same pigment. Check out Ultramarine, more variants of the exact same pigment than any other I know of (PB29).
__________________
- Delo

Delofasht
Reply With Quote
  #3   Report Bad Post  
Old 08-27-2018, 09:43 PM
opainter's Avatar
opainter opainter is offline
WC! Guide
Illinois
 
Join Date: Dec 2011
Posts: 7,384
 
Hails from United States
Re: Same single pigment different values: How?

I believe the reason Ultramarine Blue (PB29) comes in so many variants has to do with how long certain chemical processes involved in its preparation are allowed to last.

Gigalot would be able to confirm if this is the case!
__________________
AJ (opainter), C&C always welcome
:::: Helpful links for new users: User Agreement || Reference Images || C&C Suggestions || Color Theory and Mixing (color theory and color selection) || Full List of Forums
:::: Painting Blog with an article now and then

Last edited by opainter : 08-27-2018 at 09:46 PM.
Reply With Quote
  #4   Report Bad Post  
Old 08-27-2018, 11:10 PM
Delofasht's Avatar
Delofasht Delofasht is online now
A WetCanvas! Patron Saint
Town of George, Kentucky
 
Join Date: Jan 2004
Posts: 3,344
 
Hails from United States
Re: Same single pigment different values: How?

Oh yes, I know that to be the case, but it made for an excellent example. Phthalo also comes in a massive range of hues, and even more impressive comes in 7 different pigment sub codes from 0 to 6 that I am aware of, and then 3 different pigment numbers as well 15, 16, and 17. So lots of options for different hues within the same pigment family, and even within the same pigment code.
__________________
- Delo

Delofasht
Reply With Quote
  #5   Report Bad Post  
Old 08-28-2018, 08:53 AM
Burntpadua Burntpadua is offline
New Member
 
Join Date: Aug 2018
Posts: 11
 
Re: Same single pigment different values: How?

Thank you again for this. I thought that manufacturing differences might explain it, but this confirms it. I appreciate it.
Reply With Quote
  #6   Report Bad Post  
Old 09-06-2018, 02:00 AM
Patrick1's Avatar
Patrick1 Patrick1 is offline
A WetCanvas! Patron Saint
Canada
 
Join Date: Mar 2001
Posts: 3,713
 
Hails from Canada
Re: Same single pigment different values: How?

Just a guess: it might be that the Basics Primary Blue simply has less of the same pigment as Basics Phthalo Blue, and more medium or filler. If so, this could sometimes be a good thing.
__________________
Color is the most important element in painting - except for everything else
Reply With Quote
  #7   Report Bad Post  
Old 09-06-2018, 08:43 AM
sidbledsoe's Avatar
sidbledsoe sidbledsoe is offline
WC! Guide
Maryland, USA
 
Join Date: Jul 2007
Posts: 15,723
 
Hails from United States
Re: Same single pigment different values: How?

Quote:
Originally Posted by Burntpadua
How do they change the lightness when no second pigment is listed?
By variations in particle size, the physical molecular structure, heating variations, amount of moisture, etc.
Pigment numbers are designations for the general families of similarly composed pigments. There can be wide difference in their hue or color, opacity, and or tint strength.
Quote:
Check out Ultramarine,
Quote:
I believe the reason Ultramarine Blue (PB29) comes in so many variants has to do with how long certain chemical processes involved in its preparation are allowed to last.
Here are comparison micrographs I did of two PB29 ultramarine blue paints, one violet vs one green biased, both have the same pigment number.

Last edited by sidbledsoe : 09-06-2018 at 08:57 AM.
Reply With Quote
  #8   Report Bad Post  
Old 09-06-2018, 11:39 AM
Richard P Richard P is online now
Veteran Member
 
Join Date: Jul 2017
Posts: 691
 
Re: Same single pigment different values: How?

Interesting comparison micrographs!

Did you ever resolve the natural/synthetic iron oxide question?
Reply With Quote
  #9   Report Bad Post  
Old 09-06-2018, 11:49 AM
sidbledsoe's Avatar
sidbledsoe sidbledsoe is offline
WC! Guide
Maryland, USA
 
Join Date: Jul 2007
Posts: 15,723
 
Hails from United States
Re: Same single pigment different values: How?

No I didn't Richard, and no longer have access to that equipment.
Also, I am glad the first pics are still there because some of the photos in that thread have been lost over time for some unknown reason.
Reply With Quote
  #10   Report Bad Post  
Old 09-09-2018, 07:17 AM
Patrick1's Avatar
Patrick1 Patrick1 is offline
A WetCanvas! Patron Saint
Canada
 
Join Date: Mar 2001
Posts: 3,713
 
Hails from Canada
Re: Same single pigment different values: How?

Sid - I didn't see that post you made years ago - thanks it's very interesting. Surprising how much 'empty space' paint really is...I would've expected it to be literally jam-packed with pigment particles.

Do both your RS and GS have similarly dark masstone in-the-flesh?
__________________
Color is the most important element in painting - except for everything else
Reply With Quote
  #11   Report Bad Post  
Old 09-09-2018, 08:26 AM
sidbledsoe's Avatar
sidbledsoe sidbledsoe is offline
WC! Guide
Maryland, USA
 
Join Date: Jul 2007
Posts: 15,723
 
Hails from United States
Re: Same single pigment different values: How?

Patrick, as I remember I think it was thin smear on the slide. I can't tell any difference between french ultramarine and the green shade in masstone. But then when tinted out it is clearly different.

I remember getting frustrated one time, I was trying to repaint over a sky that I had done plein air, and I couldn't get close to the right hue with my ultramarine, until I finally realized that I had used green shade the first time.
Reply With Quote
  #12   Report Bad Post  
Old 09-09-2018, 12:46 PM
Gigalot's Avatar
Gigalot Gigalot is offline
A Local Legend
Tbilisi, Georgia
 
Join Date: Jun 2009
Posts: 8,844
 
Hails from Georgia
Re: Same single pigment different values: How?

Quote:
Originally Posted by Burntpadua
list PB15:3 as the only pigment.
They do not list Blank Fixe additive into PB15:3 pigment. Such pigment as PB15:3 is absolutely extremal power tinter and therefore, always have 50-60% of fillers addition. Industrial blue paint has only 3,8% of pure Phthalo PB15:3 content to achieve regular color and covering power.
Some of artists' grade PB15:3 can have transparent Aluminum Hydrate as a filler and that cause deep color, but some have Barium Sulfate addition and that gives Manganese Blue color to paint.

Last edited by Gigalot : 09-09-2018 at 12:49 PM.
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 08:36 PM.


© 2014 F+W All rights reserved.