Quality Control Issues

Because screen printed graphics is specialized and singular pursuit it employs it's own terminology and code of standards. The following is a list of anomalies that are generally considered to be defects in workmanship. While these problems are caused by difficulties inherent in the process, you have a right to expect not to see them in your finished product.


Pinholes are tiny breaks in the emulsion that coats the screen and appear as small dots of ink where there ought not to be any. While an occasional pinhole will be missed by the most meticulous of printers they can be easily removed,(except in garment dyed shirts), with what is known as a spotting gun.


Stains on the garment can be caused by a variety of factors. The printer could get a little over zealous about his inking or the folders could have a Java disaster or the mill could leak a bit of machine oil during the sewing process. Stains are clear defects and the printer should be informed about even subtle discolorations on the garment.


There are general rules for placement of an image on a garment, but since all garments are of varying dimension and proportion, exact placement can be a judgment call. It also depends on the size and shape of the image itself. The rules of thumb are: Full front- 3-4 inches down from the collar. Full Back- 4-6 inches down from the collar. Left Chest- Bottom aligned with bottom seam of sleeve.

All of these are general rules. In the end it is a an aesthetic decision on the part of the printer. If you have an intended placement that deviates significantly from the above guidelines then you should make it clear to the customer service rep before printing. A helpful technique is to take a Xerox of your image at full size and tape it onto the shirt to see how it looks. If you determine that it needs to have an unusual placement then send your 'mock-up' to the printer.


Consistency of Placement

You have the right expect minor deviation in the placement from shirt to shirt. In some cases it is quite clear where the image is in relation to the landmarks of the garment, (i.e.. the collar). In other cases, such as a left chest the exact location can be more elusive. The printer will generally load the shirt onto the platen the same way every time but even top quality shirts can be quite irregular dimensionally and often the printer must make a judgment call. If you have exceedingly specific criteria for placement consistency you should make this clear from the outset.

Color Correctness

Because the gamut for process printing on garments is much smaller than most other printing methods you can not expect colors to match exactly. A carefully engineered separation and a skilled inker should be able to deliver a pleasing print that captures the essence of the range of tones and the levels of contrast in the original, but will be unlikely to match it as well as an offset print. Often touchplates are used to achieve colors that are out of range.

Process printing on dyed shirts yields a much narrower range than on white shirts. If the result of this process looks even remotely like your original you should be pleased. For spot printing the range of colors is similar to offset. You should have no problem specifying colors from any of the standard matching systems, including Pantone, Focoltone, and Trumatch. It also helps if their ink department and print areas have a good graphic standard 5000k light source to match colors under.


Color Consistancy

Maintaining color consistency in halftone printing, especially process can be a challenge for even the most seasoned printers. Hues in process printing are determined by the proportional densities of the 4 process colors. These proportions can be disrupted by any one of the many factors that determine the amount of ink that flows through a particular screen. The most common cause of color shifts from shirt to shirt within a run is uneven platens. If the platens are not all level the critical off contact distance will change, often causing a visible shift in the hues. Process colors can be difficult to match from run to run if all of the critical variables are not recorded and controlled by the printers. This is one of the reasons process printing on t-shirts can be so ornery. The tools necessary to control this myriad of interrelated parameters are not standard equipment in the vast majority of screen print shops. The absence of tools such as deltascopes, colorimeters, off contact gauges, and print pressure meters will indicate to the prospective shirt buyer that the shop may not be capable of the consistency you see as reasonable.

Hue consistency for spot colors from shirt to shirt within a run is not ordinarily an issue, but color matching from run to run can be elusive if the shop does not employ a structured color matching system. The presence of a quality digital scale and a catalog of achievable ink colors will tell you that a printer is capable if repeatable ink mixing.

Dye Migration

This is an effect that is generally seen on shirts containing polyester. Since the dyes used for garments don't readily bind themselves to polyester fibers the shirt color can effect the printed area. This effect can be seen immediately after curing or can appear weeks after the shirts have been delivered. Red shirts with white ink are the most notorious for this effect but may other combinations can be trouble.



Scorching is caused by improper heating of the shirt between colors on press in the flashing stage or in the main dryer during curing.Scorching can evidence itself in a range of hues, from almost indetectable yellow to a Cajun blackened. Plastisol inks are the most durable but require heat to cure. Large areas of yellow or brown as well as brittle fibers are indications of a scortched shirt. Printers must strike a delicate balance of temperature and time to properly gel or cure the inks and if diligent measurements are not taken shirts can be easily torched. Occasionally, this phenomenon can be caused by sizing left in the shirts from the mill. Under normal curing conditions this sizing can create a light, yellowish cast. There are several devices that the printer can use to monitor these factors. For more details see the next section.


One of the most carefully monitored factors in screen printing with plastsols is the curing process. The ink must reach a certain temperature to completely cure. Improper curing can be seen as inks that loose much of their vibrance or opacity after washing. This should not be confused with fibrillation.

Fibrillation or Frosting

This is an effect that occurs on light shirts and is often confused with improper curing. The effect is visible on prints that employ transparent inks that use the whiteness of the shirt to achieve certain bright hues. When these inks are washed the lack of a heavy plastic coating allows some of the unprinted fibers to break through the ink layer and dull out or "frost" the image. This predicament has recently become more of an issue because shirt manufacturers have been driven by market forces to make heavier weight shirts that feel smoother. The fibers in these super heavyweight garments are the most suspectable to this effect. Process printing is the most vulnerable to frosting as all of the inks used, except black, are transparent.



The flexible nature of fabric can yield a distorted image if the shirts are not loaded correctly. The adhesive that is used to hold the shirt on the platen can catch part of the garment when it is being loaded and pull it out of shape. There are loading techniques that can alleviate this effect but certain shaped prints, such as hard geometric boxes, will show distortion much more than others.


It is difficult to describe a specific benchmark for opacity. In halftone printing it is especially problematic to balance dot gain and opacity considerations. On light shirts you should not be able to see the weave pattern of the shirt thorough the ink, even under minor stretching. On dark shirts the problem is compounded by the need to cover the shirt color with a thick enough layer of opaque lighter colors without making the shirt "bulletproof". In most cases the level of acceptability is a judgement call, so you should know poor coverage when you see it.


How well a shirt washes is determined by how well the inks are cured.



The registration tolerances of the various presses used by screen printers range wildly, but a well trained operator with decent well tuned equipment should be able to make product with very little or no visible error. The best way to achieve a pleasing graphic image is to butt register the separations, which requires nearly perfect registration to print successfully. Any gaps between colors that are visible from more than a foot or two away are generally beyond the level of acceptability.


This is term that describes the amount of ink on a shirt. In certain printing styles, such as athletic, a heavy deposit is acceptable and even, to a degree, expected. In most other styles of printing any large ink area that stiffens the fabric is objectionable. In extreme cases the weight of the ink can be felt and the print will not breathe, causing a nasty adhesive effect on the wearers chest on summer days. A decent printer will have developed a library of techniques to achieve decent coverage and avoid having to donate the rejected goods the local S.W.A.T. team.