Hallelujah! – There is finally a clear and elegant solution for the ever-present problem of doing a press-to-proof match, or doing a press check and matching a proof in the viewing booth. Most printing papers today contain optical brightening agents whose fluorescence causes the printed sample to look bluer and brighter, which is good, but then the colours do not always match the proof.
Ultraviolet (UV) radiation in a light source can hit the paper causing it to fluorescence and change colour. This UV-induced colour shift has been difficult to control causing headaches in prepress, in the pressroom and with light booth and measuring instrument suppliers. But wait – the whole industry can now breathe a sigh of relief. A new standard called ISO 13655 has recently clarified UV-included and UV-excluded measurement modes for spectrophotometers, which is likely to improve inter-instrument agreement, especially when measuring press sheets containing fluorescent brightening agents.
To avail of this new standard you have to update your equipment – you need to buy the new X-Rite eXact or i1Pro2 or the Techkon SpectroDens; and you need to put new lamps in your GTI or JUST Normlicht viewing booth. The cost of updating technology is burdensome, but any such financial pain is ultimately superseded by recent changes that allow us to now banish colour-matching woes that have plagued the industry for many, many years.
In the printing industry, one of the major considerations is the ability to deliver accurate and consistent colour to the customer. Colour matching is done using instrumentation via a process known as “printing to the numbers”. The numbers in this context are usually L*a*b* values that are measured and monitored via the use of a measuring instrument. One challenge with instrumentation has been that the UV component in the measuring illuminant of different instruments can be different, which causes different instruments to give different readings for the same sample. If the paper or ink exhibit fluorescent behaviour, then we have typically seen variations between measurement devices when measuring the same press sheet – and this causes much head scratching.
At the moment, the UV component in the light source of an instrument is not stipulated so that different devices can have different amounts of energy in the UV which lead to different measurement readings of the same sample. This means that if you used the X-Rite i1Pro instrument to make an ICC colour profile, but press side you used an X-Rite 530 handheld spectrophotometer, the press sheet and contract colour proof may not match despite full and correct application of a colour management process. Instruments up until now were not carefully regulated in the UV part of the spectrum – so different instrument families had different lamp characteristics and differing amounts of UV in their devices. As more and more printing papers started to include optical brightening agents to increase their brightness, we started to see problems which caused endless headaches in the field.
The UV in a measuring instrument represents the classic case of the observer causing an effect in the experiment that they are trying to observe because the light used to measure the sample is itself influencing the measurement. In the case of samples containing optical brightening agents (OBA), UV from the measuring light is absorbed and emitted in the blue part of the spectrum, so we are no longer independently measuring the sample because the light used to probe the characteristics of the sample is changing the sample’s characteristics. When OBAs are present, the sample’s reflectance will change with the amount of UV in the measuring instrument and different instruments from different manufacturers will compute different spectral data for the same sample.
In a simple experiment, the IDEAlliance Control Strip was printed on Epson Photo Paper and the white patch was measured using different instrument configurations. The different instruments produced varied results. The peak in the blue part of the spectrum (around 400 to 450 nm) changes depending on the amount of UV light in the measuring instrument – the more UV light in the device, the higher the peak in the blue. This difference is most evident in the white patch, but is expected to affect all colours in the control strip to a greater or less extent. We get different readings depending on the instrument used, this understandably causes problems – which reading is correct and which reading is seen by the customer in the viewing booth during the press check?
The new standard
There is an updated ISO Standard called ISO 13655:2009 graphic technology, spectral measurement and colorimetric computation for graphic arts images. This ISO standard specifies the illuminant (UV) characteristics when using an instrument to measure printed samples. A number of new devices incorporating ISO 13655 have been recently released by major suppliers, as well as a number of light booth fixtures. ISO 13655 clarifies the different UV included and UV excluded measurement options. There are now four clear and well-defined measurement modes defined as M0, M1, M2, and M3.
M0 is known as a “legacy” mode and is a standard that represents the majority of measuring instruments currently in the field today. It is directed to instruments that use an unfiltered gas-filled tungsten lamp to illuminate the sample being measured. Prior to LED-based devices, the tungsten bulb based device was the primary type of device on the market. The light contained within the instrument may approximate Illuminant A. It should be noted that in this mode the light is neither UV filtered nor polarized, and also the UV component can be very weak. In general, the M0 mode is a catch-all mode so that legacy devices can be characterized within the new ISO standard. An M0 instrument can safely be used for process control applications as it can make very reliable, repeatable measurements, but it cannot be used in situations where it is necessary to exchange information or seek correlation with other measurement scenarios because an M0 instrument may not read the same as another instrument that is measuring the same sample.
M1 is known as the “D50 mode” or “UV included” mode. A major difference (and improvement) over earlier specifications is that the amount of energy in the UV and visible wavelengths is now specified. The light source in the instrument must match CIE Standard Illuminant D50. It is useful to remember that D50 is simply a spectral curve and there may be different ways to elicit a D50 response. Generally speaking, there are two methods to achieve conformance to condition M1 – we describe these as physical (using a tailored, customized source and or imaging apparatus, as employed in the X-Rite eXact) and mathematical (using a mathematical function to approximate the required spectral power distribution, as used in the Konica-Minolta FD-7).
M2 is defined as a “UV-cut” mode. ISO 13655 states, “To exclude variations in measurement results between instruments due to fluorescence of optical brightening agents… the spectral power distribution of the measurement source… shall only contain substantial radiation power in the wavelength range above 400 nm.” How is this mode used in practice?
There will be times when a customer will request a print to be measured using M2 because the lighting used to display the job is expected to be free of UV content. A museum is an example of one of the major places that uses UV-free lighting. In colour management circles OBA induced colour shifts were often dealt with by removing UV light from both the measuring system and the viewing conditions. Now with the new standard we have a specific definition for “UV-cut” and the wavelength at which it happens. Note that the rest of the illuminant spectral power distribution for M2 is not specified – it does not have to be, as in this spectral range we are in a situation where the instrument illuminant does not interact with the specimen or change the emission characteristics, so it is not necessary to define the spectral power distribution of the source from 400 to 700 nm and a measuring instrument can simply compute the spectrum of the sample in this range.
M3 is a polarizing mode and consists of UV-cut up until 400 nm and then a polarizing filter is applied to the remaining wavelengths. As above, the illuminant spectral power distribution from 400 to 700 nm for M3 is not specified – it does not have to be, as in this spectral range we are in a situation again where the instrument illuminant does not interact with the specimen. The main use of M3 is to limit or completely remove surface reflections.
In the offset printing industry, the customer pays for the final dry product. One of the main concerns is that the press sheets come off the press wet and as they dry the density of the ink drops. The M3 mode can aid printers in cutting the surface gloss from wet inks, and if drying is primarily represented by a change in surface gloss then by removing the gloss we may have a better prediction of the final expected dry density. Because of the polarizing filter the measured density values using M3, may be different to the density achieved from the other modes. In fact, in any measurement we see that each mode (M0-M3) can produce a very different spectral response and thus any computed metrics (CIELAB, CIEYxy, density) can be different for each measurement mode.
Measuring and viewing
The instrument manufacturers have responded to ISO 13655 with the introduction of a suite of devices that all meet the M0 - M3 measurement modes. Konica-Minolta Sensing has entered the prepress market with the FD-7 spectrophotometer and a paired automatic chart reading table called the ColorScout A+. The device also measures ambient lighting – a feature not found in other similar devices. Techkon released the SpectroDens, which can be used in spot mode but also uniquely has four wheels allowing the user to roll it over control patches. Techkon also has two clever iPhone apps: iRegister Pro can be used to measure the register on a press sheet and the ColorCatcher app can measure the L*a*b* of a sample. You can use your iPhone as a measuring instrument! Note that both the iPhone apps require a small kit costing around $100.
We note that market leader X-Rite of Grand Rapids, Michigan, offers us the eXact for the pressroom and a new version of the i1Pro called the i1Pro2 for colour management users. It is important to note that neither the chart reader iSis device or the press-side IntelliTrax scanning system is compliant with the new standard and neither can be retrofitted to comply with the new standard. Users can, however, adapt their i1iO table to accommodate the new i1Pro2. When buying an instrument or upgrading your system, make sure you are using an instrument from the above list that is ISO 13655 compliant.
The clarification for illuminant in measuring instruments (ISO 13655) is accompanied by a similar clarification in the standard for viewing booths called ISO 3664. Via the updated viewing booth standard, emphasis has turned to requiring a closer simulation of Illuminant D50 thus clarifying the amount of UV illumination in the viewing booth too. The new viewing booth standard refers to issues such as excluding stray light and that the walls of the booth should be a type of neutral gray, but in the current context, ISO 3664 has called for tighter tolerances on the quality of the light source to ensure that it closely matches the D50 (M1) curve especially in the UV spectrum.
In terms of light booths, two major manufacturers in GTI and JUST Normlicht have had new light fixtures available for a couple of years now. All users should check with their representative or on the supplier Website to ensure they have ISO 13655/3664 compliant lighting.
We are at a truly exciting juncture in colour management systems – finally we have a clear specification for the UV component in both the viewing booth and the measuring instrument. Together, these systems are able to deal with the challenges of OBA-induced colour changes that have plagued our industry for a long time. If a viewing booth is fitted with the new light sources and we use a new measuring instrument in M1 mode, then visual appraisal of press sheets and contract colour proofs will always be in agreement.
Measuring instruments are supposed to provide a reliable and robust method for colour measurement. Unfortunately, in the case of UV and OBAs there has been considerable confusion and lack of inter-instrument agreement. The new ISO 13655 standard for instruments and ISO 3664 standard for viewing booths will greatly reduce the colour matching problems currently faced in the field.
Dr. Abhay Sharma is a professor at Ryerson University’s School of Graphic Communications Management. Dr. Sharma is active in print media research and recently coordinated the IDEAlliance Wide/Grand Format Inkjet RoundUP study. He can be reached at
After Benny Landa and the introduction of the nanographic printing process, the biggest attraction circling the print industry is arguably 3D printing. At the recent Graphics Canada tradeshow, I found it quite interesting to see 3D printers for the first time with my own eyes and being able to hold products in my hands after they were made on the devices at the show. The 3D printers on display included a small single colour device retailing for about $2,500 and a two-colour device for around $4,000. As with the aging path of any new technology, prices will most likely come down as more devices find their way into the market.
The arrival of 3D printing spread across the public’s consciousness earlier this year when the plans for producing a gun using 3D technology were made available on the Internet. The only metal part was the pin used to fire the bullet. Frightening scenarios were painted about the consequences of allowing anyone with access to a 3D printer to produce such a gun, because – among a raft of grizzly schemes – the plastic parts would not be detected by conventional airport security scans. After a deluge of online protest, the person who posted the plans for the gun removed the files, but as we all know they were probably copied countless times and still readily available.
The technology of 3D printing, however, is touted as the next great thing in customer service. If you need a part for anything, just 3D print it and you can repair whatever is broken. It has also been suggested that 3D printers will make extensive toolkits obsolete, since you can produce the tool that you need right there, assuming you have a 3D printer in your home or workshop. The relatively inexpensive 3D printers use molten plastic to create the objects, others, more expensive ones, employ metal powder which will be hardened through the application of a laser beam or electron beam.
High-quality 3D printing is achieved with stereolithography. It is a polymer-based process. A laser beam is directed at a bed of liquid resin and the energy from the laser causes a thin layer to harden. The laser is directed by a small movable mirror across the whole manufacturing table. The hardened material is attached to a platform that moves away from the bed of molten resin. A good animation of this process can be seen at formlabs.com/products/our-printer. 3D printers using this technology will come down in price, because some patents in regards to the technology will expire in 2014. This technology deposits layers that are 25 micrometres thick, while the molten plastic deposit method creates layers of about 100 micrometers.
It was also suggested that 3D printers should be on board of future space explorations to lower the weight of items, i.e. toolboxes, that need to be brought on the trip into space for any kind of repairs. That would leave more room for the payload that is transported into space. Artists have also discovered 3D printing as an art form. One of them is using a special technique to 3D print objects into sand, by injecting it with a special polymer, which bonds the sand particles together and hardens when it comes in contact with air. Once the printing process is complete the object gets carefully dug out of the sand. Any remaining loose sand is washed away with water.
The possibilities for printing 3D objects are endless. At the Graphics Canada trade show I had a soft silicone model of a human heart in my hands and it was printed from actual MRI images of someone’s heart. I found this simply amazing. Aside from all the great and astounding things that can be established using 3D print technology one still needs to ask oneself the following question: Is 3D printing printing or is it manufacturing?
You could make the argument that printing also deposits something, although a rather thin film of ink, onto a substrate. 3D printing also deposits material, but in much thicker layers. Printing is also quite often called highly customized manufacturing. Each job is unique and sometimes very intricate techniques are used to create the product the customer desires. This was clearly visible in some of the pieces that were entered into the Canadian Printing Awards competition. Printing is quite often used to create many copies of the same product, just like in mass manufacturing. So you can twist and turn it anyway but it starts to get a bit difficult and not very well defined.
Let’s have a look at Merriam-Webster’s online dictionary for the definition of printing: The process of producing books, magazines, etc. by using machinery the act or process of printing a set number of copies of a book at one time handwriting that uses separate letters that do not join together.
Now let’s have a look at manufacturing in Merriam-Webster’s dictionary: The process of making products especially with machines in factories.
The definition of manufacturing might need some updating in regards to the word factories, when 3D printers are more and more available to the general public.
I thought about this discussion for some time and what could be the distinguishing factor to call 3D printing a printing process or more traditional manufacturing process. In my opinion the distinction comes in regards to the fact the printing always involves images and text and in the conveying of information, regardless of what the information is.
3D printing, in my opinion, resembles a more traditional manufacturing process. The reason for this conclusion came in the form of an air nozzle that was shown to me at Graphics Canada. It is the nozzle that is above every seat in an airplane. These nozzles are now made using 3D printing and 3D printing has simplified the process, since no molds are needed to create the separate parts and then have them assembled. The nozzle is manufactured in one step with a 3D printer.
A recent article from InkWorld by Rodman Publishing states that Messe Düsseldorf, the organization that hosts the drupa and Interpack and many other tradeshows on the Düsseldorf fairgrounds, launched the 3D fab+print during the K 2013 trade show, the tradeshow for plastics and rubber. Shows and exhibitions related to 3D fab+print will be co-located with seven tradeshows and one of is drupa, which will run from May 31 to June 10, 2016.
There are many manufacturers of 3D printing equipment and, just as in the printing world, there are devices for home use, professionals and industrial scale applications. MakerBot is a well-known American manufacturer of 3D printing. A visit to the company’s Website shows that they have three stores in the United States and all 48 Microsoft stores in the U.S. have MakerBot systems installed. The next time you travel to the U.S., look up if there is a Microsoft store in the city you are visiting. You can have a look at the MakerBot 3D printing and probably for a minimal fee have a product made right there on the spot.
3D Systems is a leader in the consumer sector and Stratasys is, according to InkWorld magazine, the world leader in the professional sector. Stratasys offers up to 150 different types of photopolymers and thermoplastics – the largest selection of materials for 3D printing.
The leader for industrial applications using laser-sintering technology is EOS GmbH from Germany and its customers include well-know names like MTU (a manufacturer of large diesel engines and complete propulsion system), EADS (European Aeronautic Defence and Space Company), Daimler and BMW. These companies already use 3D printing in their production lines.
Regardless of the material and fusing technology being used in 3D printing, it must be considered as additive manufacturing. The object is built layer upon layer and the thickness of the layer varies with the deposit and fusing method that is used. The fusing method can incorporate chemical and/or physical processes, precipitation curing and/or melting. These fusing methods currently allow the use of materials like artificial resins, plastics, metals and ceramics in powder form and paper. They use methods like selective laser melting, electron beam melting of metals, selective laser sintering for plastics, stereolithography, digital light processing, polyjet modeling for photopolymers and fused deposition modeling for thermoplastics (FDM). FDM is most popular method for 3D printing.
3D printing is already used a lot more than one would think in a range of production and manufacturing environments. I think this alone settles the debate whether it is akin to printing or a more traditional production process. Malcom Keif from CalPoly University in San Louis Obispo predicts that 3D printers will invade the office like the copy machine has.
Over time, these devices will become more sophisticated and there will be different levels of sophistication with machines, again depending on if the end-use is for consumers, professionals or industrial companies. 3D printing will be part of the manufacturing world and we have not seen the end of the development yet. Au contraire, we are at the beginning of this oddly quiet manufacturing revolution.
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