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The process of offset printing in full color consist of Cyan, Magenta, Yellow and Black (CMYK). When the need to match a particular color (a background or specific color in a logo or company color) on a printed piece, the use of a spot color is utilized. The main reason that the spot color is utilized is to maintain the color fidelity or accuracy of the color throughout the print run.
Normally any or mostly any color can be created from the CMYK color model, but when large areas are being printed with the specific need of a special color, the control envelope on the printing process is limited, and sometimes a compromise on color is required. An example is an image that has a blue sky (Cyan and a hint of Magenta), and green grass (Cyan and Yellow) has the requirement of any of the base colors being used (Cyan, Magenta and Yellow in this case) for the special color - say Purple (almost equal amounts of Cyan and Magenta) , then the amount of the contributing color to the special color will be limited to either be the correct amount for the green grass, the blue sky or the Purple special color, all three demanding different degrees of Cyan.
The printer needs to have a special file created for the spot color in addition to the CMYK colors. This spot color will eventually be a plate that utilizes an extra printing unit on the press to print the color to the printed sheet.
There are several systems developed and in place for matching specific spot colors in the industry. In North America, the most common has been designed by Pantone Inc. The matching system developed by Pantone is called "Pantone Matching System" (PMS) and this system has approximately 1,000 different pre-defined colors that can be mixed from an array of base inks that are called "Pantone Colors" - these Pantone colors are the base inks that are sold by the company. A printer normally refers to the PMS number of the ink in the specification. Once the specification is established, the client and the printer refer to the color by its PMS number.
To print in the spot color, the printer will take the specified PMS number, refer to it in a Color Chart which identifies the Pantone Colors (Base colors) that will be required to mix the PMS numbered ink, and further the percentages to be mixed to achieve the desired color. Computerised scales are available to printers with high volumes or the requirement to be accurate. The color achieved by the compterised scales are achieved faster and with less waste. This offers efficiency to the printer who can thus offer cheap printing of business cards, flyers, post cards, brochures, catalogues, and books.
The PMS color mixed to achieve a color on coated paper will print with a different hue and density on offset stock, non white or off white stocks. This is the reason that the company that establishes these matching standards offer color swatch books in both offset and coated stocks. Printoutlet utilizes a computerized system to achieve the exact color that is required, thus reducing errors.
It is possible to mix two or more spot colors to create further colors with interesting effects. This practice is employed in the 2 color duotones (an image printed in 2 colors only) or tritones (an image printed in 3 colors only) - Although it is possible to use this process for 4 colors (quadtones), it is not used as often as the variety of interesting effects it offers as the special washes and mixing charges that go with the use of spot colors is prohibitive.
The use of the base Pantone colors is also possible in the printing process, and are employed extensively, such as Reflex Blue (a Dark Blue Color) - a Base Pantone Color that is used very often as a special spot color in a printed piece.
The proofing of spot colors is not conquered in the Digital process of todays printing technology, but since a spot color is defined as a specific number in a matching system, its reproduction is almost always assumed to follow a PMS Guide or color chart. Some analogue processes have offered a proofing process by means of an image on a laminated layer on clear acetate, but the yellowness of the acetate, especially when several layers are utilized, renders this process a guess at best for the representation on the proof.
INFO BELOW FROM :
http://www.castleprint.co.uk/spot-process-colours.html
INFO BELOW FROM :
http://www.castleprint.co.uk/spot-process-colours.html
Problems producing stationery using both spot & process colours
Let's say your company design uses 2 colours: Pantone 021 (Orange) and Black.
Let's also assume you require Letterheads & Business Cards.
Letterheads
The 2 colours would be set up on the press and if the orange (021) was later compared to a Pantone swatch then you would see that the match is very, very close. So far, so good.
Letterheads
The 2 colours would be set up on the press and if the orange (021) was later compared to a Pantone swatch then you would see that the match is very, very close. So far, so good.
Business Cards
You've decided, for whatever reason, to use a solid colour on the front or reverse of the card and you also want this
matt-laminated. Due to cost, most commercial printers (ourselves included) would produce these cards using a 4 colour process (CMYK). The reason for this is that it is too expensive to set up a printing press with 2 spot colours and then laminate these cards.
It is far more cost-effective to plan multiple card jobs together, run on one large sheet, and then laminate the whole lot as one group. As all the cards will probably have different colours the way around this is to produce them from the 4 CMYK colours, Cyan, Magenta, Yellow and Black.
However, the downside to this is that when certain spot colours are converted to CMYK, (our Orange 021 for instance), there can be a distinct colour difference due to technical problems with certain colours.
matt-laminated. Due to cost, most commercial printers (ourselves included) would produce these cards using a 4 colour process (CMYK). The reason for this is that it is too expensive to set up a printing press with 2 spot colours and then laminate these cards.
It is far more cost-effective to plan multiple card jobs together, run on one large sheet, and then laminate the whole lot as one group. As all the cards will probably have different colours the way around this is to produce them from the 4 CMYK colours, Cyan, Magenta, Yellow and Black.
However, the downside to this is that when certain spot colours are converted to CMYK, (our Orange 021 for instance), there can be a distinct colour difference due to technical problems with certain colours.
What this means is that the colour of your cards can end up being totally different from the colours on your letterheads. Note - it is not all spot colours that convert badly to CMYK, but just some that seem to suffer from the conversion.
Workaround?
One workaround is to print the cards first, and then 'match' the letterheads to this colour (spot colours can easily be 'adjusted'). The problem then is that although you end up with matching stationery, all of a sudden it's not Pantone® Orange (021) anymore, as we've now matched to a CMYK colour.
One workaround is to print the cards first, and then 'match' the letterheads to this colour (spot colours can easily be 'adjusted'). The problem then is that although you end up with matching stationery, all of a sudden it's not Pantone® Orange (021) anymore, as we've now matched to a CMYK colour.
If your shade of colour is critical then, unless you've had previous cards that are acceptable, it's probably best to steer away from cards produced using CMYK. Do not be alarmed as this problem only applies to certain spot colours so check with your printer to see if your particular Pantone colour converts accurately to CMYK or is one that can cause issues.
We have a list of certain colours that cause problems and we would notify you during the artwork process if this was applicable to your brand colour.
To recap - if you want your card matt-laminated and also for the card to match existing stationery, then it would definitely be worth checking with us first to see if there may be any colour-matching issues.
If you are at all concerned about achieving colour consistency across all your printed products, whether stationery or promotional items please see a fuller explanation of the above issues, posted < HERE >
If you're wondering how to access the colour swatches in Illustrator, well the guys at Adobe have moved it to a different part of the menu system.
If you're wondering how to access the colour swatches in Illustrator, well the guys at Adobe have moved it to a different part of the menu system.
Just click on: Window (in the main file menu), select: Swatch Libraries and then Colour Books.
Which swatch to use?
For our purposes, it doesn't really matter whether you select uncoated or coated, as the material and the print process will determine which type of ink is used for your project. For instance, if you're having some leaflets printed on gloss art paper, then the printer will use a coated ink, which has been designed to dry quickly on this type of surface.
Business cards, letterheads etc. will generally be printed using uncoated inks. I would recommend not worrying too much about this aspect, and choose a 'regular' colour book such as Pantone Solid Coated and stick with it for all your tasks.
The important thing to remember is to stick with one colour book on a project, i.e. don't mix coated and uncoated or any other book in a single project.
If you're not using spot colours in your project, but have used them to select the colours you require, don't forget to convert them all to CMYK.
Business cards, letterheads etc. will generally be printed using uncoated inks. I would recommend not worrying too much about this aspect, and choose a 'regular' colour book such as Pantone Solid Coated and stick with it for all your tasks.
The important thing to remember is to stick with one colour book on a project, i.e. don't mix coated and uncoated or any other book in a single project.
If you're not using spot colours in your project, but have used them to select the colours you require, don't forget to convert them all to CMYK.
This is easily done by selecting them one at a time, and then using Select > Same > Fill Colour to select all similar colours and then converting using the 4 colour icon shown below. If you don't see this box, then hit F6 to display it.
Any spot colours left behind probably won't print, so do make sure you've converted them all, including any 'strokes' that are in spot colours.
Any spot colours left behind probably won't print, so do make sure you've converted them all, including any 'strokes' that are in spot colours.
After conversion you can see that Pantone 247 is made up of 36% Cyan & 100% Magenta, with no yellow or black (K).
How do I convert a CMYK colour I've been given, back to its Spot Colour equivalent?
This is a question often asked!
There are a couple of options, an expensive one and another that just takes a little time.
The first option is to purchase a Pantone swatch that shows the spot colour equivalents of CMYK 'splits'. That's the easy way, but for occasional use a little too expensive.
Another way is this:
There are a couple of options, an expensive one and another that just takes a little time.
The first option is to purchase a Pantone swatch that shows the spot colour equivalents of CMYK 'splits'. That's the easy way, but for occasional use a little too expensive.
Another way is this:
Firstly, write down the CMYK colour split you're looking to find a spot colour equivalent for. For the purposes of this exercise, I've chosen the following split:
C = 51%, M = 0%, Y = 9% K = 0%
Now, draw a box in your illustration program and fill it with the above split.
C = 51%, M = 0%, Y = 9% K = 0%
Now, draw a box in your illustration program and fill it with the above split.
Draw another box below your original and choose a colour as close as you can from the Pantone swatch of your choice. (I normally use Pantone Solid Coated). In this instance I went for Pantone 311.
With so many blues to choose from you'll be lucky if you get really close the first time.
With so many blues to choose from you'll be lucky if you get really close the first time.
OK, you've chosen a blue and now need to convert this to CMYK in the usual way, using the 4 colour icon.
Pantone 311 has split to 63, 0, 12 & 0. Not bad, but a little on the dark side, (scary!), so we need to try another colour.
I've now selected Pantone 305 which looks pretty good, so again we need to convert it to CMYK. Fingers crossed.
Spot on. Our 51, 0, 9, 0 split converts perfectly to Pantone 305 so we now have our working spot colour.
Hope this helps!
However, if any points need clarification or you just need a little help please don't hesitate to contact us, and we'll do our best to assist.
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