Put the image to be cleaned onto a sheet of glass (light table) or onto the emulsion side of a clean old scrap RC print. Dispense a few drops of PEC-12® Film Cleaner onto a clean PEC PAD®. With the gentle pressure of two or three extended fingers, start at one end of the film/print to be cleaned and smoothly move your fingers toward the opposite end in a straight line removing contaminants from the emulsion by transferring them to the PEC PAD®. Extremely grimy stains (such sticky tape residue) may need a second or even a third pass (using a clean PEC PAD® and additional PEC-12® Film Cleaner application). Any material applied with enough pressure will ultimately cause scratches, but normal, prudent use of PEC PAD® Lint-Free Cleaning Wipes will provide scratch-free cleaning of slides, negatives, and prints.

For ground-based astronomy, CCDs have been the most used technology. However, CMOS technology has improved with the advances in lithography technology improving the optical sensitivity.

PEC PAD®s are NOT recommended for cleaning CCD sensors in 35mm DSLRs. Because Photosol cannot control how carefully you handle the material while storing, folding, assembling, or applying Eclipse® Optic Cleaner or Aeroclipse®, Photosol cannot approve or warranty the CCD or any camera part from any damage caused by homemade swabs or kits assembled by third party resellers.

CCDs are increadibly powerful tools for astronomers because when a telescope's motion is synchronized with the Earth's rotation, the camera can “stare” at one spot in space for hours at a time. The longer the CCD is exposed to the sky, the more photons will land on it, and fainter, more distant objects can be imaged than are otherwise visible. CCD exposures are so long in astronomy (seconds, minutes or even longer) compared to digital cameras (normally a fraction of a second), that CCDs in telescopes are usually kept very cold (−50°C to -100°C). Keeping the CCD at a very low temperature minimizes the effects of thermal noise. At any given temperature, a certain fraction of the electrons in the atoms of the CCD itself will have enough thermal energy to liberate themselves. They are then indistinguishable from electrons liberated by the interaction of the CCD with incoming photons from the telescope, so they get counted as if they were light from a star.

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Joe Tufts: Astronomical CCDs vs. Light Sensors In A Digital Camera Astronomical CCDs are similar to the sensors in your digital camera in that they both use the same underlying physics to detect light, Einstein's photoelectric effect, but that's where the similarities end. The CMOS device that's likely in your digital camera is really an array of millions of independent light sensitive photodiodes called pixels bounded by structure etched into the silicon itself. Each pixel is in turn connected to 3-7 transistors which together make up an electronic structure called a source follower, buffer, or simply an amplifier. In an astronomical CCD the boundaries of individual pixels are, in a sense, defined electronically, so that the charge created by the photoelectric effect and stored in each pixel can be moved about the sensor to a single larger and much more precise source follower. The end result is that the astronomical CCDs are more flexible and have less noise than your digital camera. The downside is that CMOS devices in digital cameras are much faster than CCDs.   The other important difference is that astronomical CCDs are typically used upside down. All of the electronic structure etched on to a CCD or CMOS device is on a single surface of the silicon wafer. If you think of this structure as wires, and bridges, and walls, its easy to see that the more of it you have, the less room there is to collect incoming light. Astronomical CCDs are illuminated from the back where there is no structure, and through a process called depletion, electric fields are created within the silicon which rapidly move the charge created by the photoelectric effect on the back into the "buckets" on the front. To do this efficiently, the silicon needs to be very thin, anywhere from the thickness of an index card to the thinness of the thinnest tissue paper, so most astronomical CCDs are termed "back thinned." The end result is that astronomical CCDs can often detect 90-95% of the incoming light compared to typcially 40-60% for CMOS sensors in digital cameras.

A CCD is a tiny microchip onto which the light that the telescope collects is focused. The microchip consists of a large grid of individual light sensing elements called pixels. Each pixel is very small, about a 10 micrometer(µm) square printed on a cracker sized piece of silicon ~50µm thick. Tissue paper is about the same thickness. The images below are of astronomical CCDs from one of LCO's telescopes and show the front and back of a CCD.

PEC PAD® Lint-Free Cleaning Wipes are NOT recommended for cleaning image sensors or CCD sensors in 35mm DSLRs. If you need to clean sensors, the manufacturer recommends using SensorSwab Ultra.

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For maximum cleaning power, use PEC PAD® Lint-Free Cleaning Wipes with different cleaners formulated for use with delicate surfaces.

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A CMOS device is a complementary metal-oxide-semiconductor (CMOS) active-pixel sensor. CMOS devices are used in digital cameras such as mobile phone cameras, webcams, and DSLR cameras. A CMOS device contains an array of individual photodiodes called pixels etched into the silicon chip, and transistors to amplify the signal from each individual pixel. They combine both the image sensor and image processing functions in an integrated circuit.

PEC PAD® Lint-Free Cleaning Wipes can be safely used on all hardened photographic emulsions, including films and papers. Extreme care must be used with 35mm chromogenic film because the base of these films are very easily scratched. PEC PAD®s can also be used on coated or uncoated photographic lenses, binoculars, and telescopes without scratching delicate coatings.

When properly used with Eclipse® Optic Cleaner or Aeroclipse®, PEC PAD® Lint-Free Cleaning Wipes make it possible to clean only the dirty portion of a lens or other optical surface to eliminate hazy swirls.

Purity and quality of all Photosol products are guaranteed. The NatureScapes Store is an authorized online retailer of Photosol cleaning products.

Charge coupled devices, or CCDs, are sensitive detectors of photons that can be used in telescopes instead of film or photographic plates to produce images. CCDs were invented in the late 1960s and are now used in digital cameras, photocopiers and many other devices. Its inventors, Willard Boyle and George E. Smith received the Nobel Prize in physics in 2009 for their work.

When gently used, PEC PAD® Lint-Free Cleaning Wipes are safe to clean plexiglass and are ideal for cleaning picture frames, glass, CDs etc.

If you’ll be traveling and are looking for a cleaning kit with a little bit of everything, check out the Digital Survival Kit by Photosol (sold separately). The Digital Survival Kit is also a great way to try out a range of Photosol cleaning products before purchasing them full size.

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PEC PAD® Lint-Free Cleaning Wipes are extremely soft and so versatile they can be safely used to clean different types of sensitive surfaces.

When cleaning with PEC-12® Film Cleaner one pass with very light pressure will clean non water-based stains. If one light pass doesn’t appear to have an effect on a stain, it may be water-based and further rubbing will not help, and may damage an emulsion. When cleaning areas which are heavily soiled (laser separation oil, heavy ink marks, tape residue, etc.) use more than one PAD to avoid smearing the stain. You may rotate the PEC PAD® to expose a clean area and thus clean several images before discarding.

Simply dispense several drops of solution onto a clean, folded PEC PAD® and lightly wipe the surface in a single direction. Start at the center and work your way to the outer edge. Slide the PEC PAD® off the edge of the lens—never from the center. Handle the PAD as little as possible to minimize transference of finger oils. Refold pad to expose a clean side and re-wipe the surface as necessary.

When light falls onto one of the pixels, electrons are released from atoms in the pixel. To measure the amount of light that fell onto each pixel, the number of electrons that was released has to be counted. This is done by measuring the charge on the pixel at the end of the last row in the grid. Then that charge is discarded and all the other charges in the row are made to move along to that one corner pixel. The next charge in line is then measured, and so on – until all the charges in that row have been dealt with. Then all the charges in all the remaining rows are made to move over one row, and the whole process is repeated. Amazingly, the entire chip can be "read" in less than 10 seconds. It is this method of read out that distinguishes CCDs from other devices (such as photodiodes and CMOS devices) that convert photons to electrons.

PEC PAD® Lint-Free Cleaning Wipes are specialized for cleaning critical surfaces without causing scratches or damage of any kind. PEC PAD®s are durable, free of lint, non-abrasive, and 99.999% pure.

CCD readout compared to CMOS. Photon to electron conversion happens at each pixel. For a CCD, the electron charge is then passed along the line of pixels and converted to a voltage at an output node at the end of each line. In contrast, for a CMOS device, the electron charge is converted to a voltage at each individual pixel. Image credit: Stefano Meroli, Engineer at CERN