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Calibration
This refers to the process of setting a device to known colour conditions.
Calibration must be performed externally for devices whose colour
characteristics change frequently, e.g. monitors because phosphors lose
brightness over time, and on printers because proofers and other digital
printing devices can change output when colorant or paper stock is changed.
Calibration is not required for most input devices (e.g., scanners and cameras)
since these devices are generally self-calibrating. If your monitor and printer
have been properly calibrated you can expect the stock photo you chose online
will look the same as the final print. Calibrating a monitor includes adjusting
its settings to compensate for the conditions you are working in (i.e. some
monitors are viewed in natural light, others under artificial light), and
ensuring that your computer has the correct colour settings for the printer. If
the monitor you use for finding stock photos cannot be accurately calibrated
(perhaps because your printing is a handled by a third party), you should add a
step to your final image selection process that includes viewing the images on a
calibrated monitor.
CMYK
Stands for cyan, magenta, yellow and black which are the four so-called process
colours that are used in four-colour printed printing (often miscalled 'full
colour printing' which is completely wrong as there are printing methods that
use more colours to get more precise results). They represent the subtractive
colour model, where a combination of 100% of each component yields black and 0%
of each yields white. Cyan, magenta, and yellow are the subtractive complements
of red, green, and blue respectively.
Whereas RGB monitors emit light, inked paper absorbs or reflects specific
wavelengths. Cyan, magenta and yellow pigments serve as filters, subtracting
varying degrees of red, green and blue from white light to produce a selective
gamut of spectral colours. Like monitors, printing inks also produce a colour
gamut that is only a subset of the visible spectrum, although the range is not
the same for both. Consequently, the same stock photo displayed on a computer
monitor may not match to that printed in a publication. Also, because printing
processes such as offset lithography use CMYK inks, a stock photo, which is
usually supplied as RGB to give the designer, must be converted to CMYK colour
to enable use. When the conversion takes place, colour shifts can occur on RGB
colour that has no CMYK representation (and is therefore compressed to fit the
model). When this colour compression happens, there are inevitably going to be
colour shifts (particularly in the intense Reds, and Greens) which is why it's
important to choose a supplier that has experience of dealing with this process.
Characterization
This is the process of creating an ICC profile that describes the unique colour
characteristics of a devices used to process your stock photo, such as a
monitor, scanner, colour printer, and printing press.
Comping image
A low resolution stock photo used for non final layouts.
Continuous tone
A continuous tone results when a stock photo has not been screened and contains
gradient tones from highlight to shadow. The original can be either black and
white or colour and contain no dots.
Convergence
This occurs in an RGB monitor, where red, green and blue signals all "converge"
in one pixel. At full brightness, the RGB pixel in convergence would be white.
Digital proof
This is a proofing system that does not include the use of film. Data is sent to
a printer and imaged directly onto a paper-based material. There are several
limitations of a digital proof: 1) they do not use the film that will be used to
produce plates, and thus are open to interpretation of the output device, 2) few
of these devices print in the same dot pattern as is utilized in the printing
process, and 3) the ink utilized in these printers is not representative of the
inks used in the printing process and can show a vast colour range and density
not attainable on a printing press. Digital proofs are usually used where money
or time is too much of an issue to run a wet proof.
Dimensions
Height and width, measured in centimetres or inches that a stock photo should be
output at. Height is generally given first in Europe but the opposite is true in
the US. CHECK THIS
DPI
Stands for dots per inch. This measures the resolution or the number of dots in
a stock photo that a printer can print or the number displayed on a screen per
inch both horizontally and vertically, and therefore is also an indicator of
quality of output. As an example, a 600 dpi printer can print 360,000 (600 by
600) dots on one square inch of paper.
Halftone
When a stock photo is looked at through a screen that converts the image into
dots of various sizes. When printed, the dots merge to give an illusion of
continuous tone to the naked eye.
HSB
This stands for hue (the pigment); saturation (the amount of pigment) brightness
(the amount of white included) in a coloured stock photo. With the HSB model,
all colours can be defined by expressing their levels of hue, saturation and
brightness in percentages.
ICC device profile
This is a file that describes how a particular device reproduces a stock photo's
colour. It does this by transferring the critical information that the devices
need regarding the intended colour levels of the output. Generic profiles are
created by the device manufacturer, who examines the colour characteristics of a
group of the same devices under controlled conditions, and then use this
information to create a profile.
Gamut
This means every colour combination that is possible to produce with a given set
of colourants on a given device or system.
Imposition
This is the process of laying out pages in a press form so that they will be in
the correct order after the printed sheet is folded.
Interpolation
The process of increasing the resolution of a stock photo
JPEG
Stands for Joint Photographic Experts Group and is the most common compressed
standard for high resolution stock photos.
Line Screen
This is the resolution of a halftone, expressed in lines per inch.
Lo-res
This is short for low resolution. If you use a lo-res stock image it will result
in low quality reproduction because of a small number of dots or lines per inch.
LPI
This stands for lines per inch and is a measure of resolution for halftones
Model release
This is a signed release from the person/s depicted in a stock photo, giving
consent for his or her likeness to be used for commercial purposes as described
in the release. It is your responsibility to ensure that you have the correct
model releases for your licence use and that you comply with the relevant local
laws. For more information see our release information page.
Page formats
The standardised sizes used across the industry are as follows.
PANTONE Colours
A colour system of over 1200 standard colours developed by Pantone, Inc. The PMS
Pantone Matching System is a swatch book that describes colours by assigning
them numbers.
PICT
A stock image file format developed by Apple Computer, Inc. for use on Macintosh
computers. The PICT format is adequate for storing and displaying data at 72
dpi, using the Macintosh screen, but is not sophisticated enough for
higher-quality work.
Pixel
This is an acronym for Picture Element. When an image is defined by many tiny
dots, those dots are pixels. A pixel represents the smallest graphic unit of
measurement on a screen. The actual size of a pixel is screen-dependent, and
varies according to the size of the screen and the resolution being used.
Pixelated
This refers to an image that is of poor quality because the balance between
resolution of the image and the output is not correct, e.g., if 72dpi images are
enlarged by 200% without using proper upsizing processes, such as interpolation.
If this happens, the monitor would display each pixel of the stock photo spread
out over 2 pixels of the monitor's resolution so the naked eye can distinguish
the pixels in it, giving a jagged effect.
Process Colour Printing
Refers to the re-creation of colour by combing two or more of the cyan, magenta,
and yellow colours, plus black.
Property release
This is a signed release from the owner/s of property depicted in a stock photo,
giving consent for the image depicting his or her property to be used for
commercial purposes. It is your responsibility to ensure that you have the
correct property releases for your licence use and that you comply with the
relevant local laws. For more information see our release information page.
RGB
Computer monitors and TVs emit colour as RGB (red, green, and blue) light.
Although all colours of the visible spectrum can be produced by merging red,
green and blue light, monitors are capable of displaying only a limited gamut of
the visible spectrum. Abbreviation for red, green, blue; the colours used in
displays and input devices. They represents the additive colour model, where 0%
of each component yields black and 100% of each component yields white. Red,
green and blue are the additive complements of cyan, magenta, and yellow
respectively. Most stock images are supplied as RGB
Raster Image
This is an image displayed as a series of lines of dots or video 'blips'. When
used in relation to a stock photo, it could refer to an image that has been used
at the wrong resolution (see pixelated)
Resolution
This is a measure of stock photo output capability (depending on the fineness or
coarseness of the digitized stock photo), usually expressed in dots per inch
(dpi). It also measures of halftone quality, usually expressed in lines per inch
(lpi).
Rights protected
This is a term used for exclusive usage of a traditionally licensed stock photo.
Rights protection can be an advantage for high-profile projects as it can
guarantee some exclusivity. The buyer obtains exclusive use of a stock photo
under the terms of the license. These terms may affect the use, media, territory
and/or duration in which the stock photo can by used by other buyers. Total
protection can be offered to coverall these terms. Pricing for this type of
license varies depending on the terms requested. Rights protection is offered
only offered for your stock photo purchase when the phrase 'Rights Protection'
appears above the calculator.
Screen Ruling
This refers to the number of lines or dots per inch in both directions on a
contact screen used to make halftones or separations. Screen rulings are
available from 65 lines per inch to 200 lines per inch. For colour separations,
however, it is best to use 150 line screens to get the best visual output.
Special
This is a specific colour designated to be printed with a specific matching ink,
rather than through process CMYK printing.
TIFF
This is the most common and compatible form of digital stock photo format, this
format is uncompressed but gives the highest quality output.
Traditionally licensed images
Traditionally licensed images, which are presented on our system by the letter L
can be either non-exclusive or exclusive and means that the image is licensed
for a specific use. For a non exclusive stock photo, the buyer pays a licence
fee each time they use the image, but another buyer can also purchase and use
the image under the same license. The buyer must also specify, each time:
intended use, media, territory and duration, and pricing is based on this
criteria.
Exclusive options for your licensed stock photo purchase are available only
where the phrase 'Rights protected?' appears underneath the price calculator.
Please see Rights Protected images for more information.
Royalty free images
Pricing is based solely on the size of output and resolution required, not the
specific image use. Once you purchase a royalty-free image, you may use it
multiple times for multiple projects though for each project you should check to
see whether a Model or Property Release is required for that usage.
Saturation
This refers to the density of a colour
Upsize
Refers to an increase in the resolution of a stock photo. Also see interpolation
URL
This is the address of a computer or a document on the Internet that consists of
a communications protocol followed by a colon and two slashes (e.g. http://),
the identifier of a computer (e.g. www.m-w.com) and usually a path through a
directory to a file.
Wet proof
This is a colour proof made from the separations supplied. The wet proof
represents the definitive printed colours and is used by the printer as a colour
match.
Source: Alamy Images |
Agricultural
stock photos
