Because of the way that it is manipulated in a dark field microscope, light passes through the condenser’s outer edge at a wide-angle, then strikes the sample at an oblique angle. This causes the light scattered by the sample to reach the objective lens, while other light that merely passes through the specimen misses the objective. The result is a brightly illuminated sample on a dark background.

Pilkington, Ben. (2022, January 20). What are Dark-Field Microscopes?. AZoOptics. Retrieved on December 17, 2024 from https://www.azooptics.com/Article.aspx?ArticleID=2125.

Phase contrast microscopy

Zernike, F. (1955) How I Discovered Phase Contrast. Science. Vol 121, Issue 3141, pp. 345-349. https://doi.org/10.1126/science.121.3141.345.

Pro’s:– No printing, cutting, sticking, tracing etc.– Time saving, you can get to the sewing much quicker– Can grade easily– Can try multiple new patterns and styles very quickly– No storing of patterns– Layers on the pdf make it incredibly easy to see which size you are cutting– Fabric pattern matching or placement is easier to see while you are cutting

There are 2 types of projectors being taken advantage of at this point. Ultra short throw projectors, or ceiling mounted.

In this interview, Patrice Dionne, M.Sc, the product line manager for optical sensing at TeraXion, talks to AzoOptics about TeraXion's motivations and innovations in DFB laser technology and various real-world applications where their technology truly shines.

Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.

LIS Technologies is on the road to transforming nuclear fuel enrichment through advanced laser techniques, ensuring a sustainable and cost-effective approach to energy production.

Any specimens in liquid samples can still be viewed with dark-field microscopy, particularly those that need to be seen with all the debris in the liquid.

Dark fieldmicroscopy

A normal student microscope can be set up for dark-field microscopy by ensuring that light will only reflect from the surfaces between the coverslip and slide, but not from surfaces beneath the slide. Occulting discs can be easily prepared by cutting circles of black electrical tape in different sizes. These can be placed on the slide, evenly spaced in a row. Depending on the configuration of the microscope, a stand may be required to hold the slide in the correct position.

Chambers, W., T. J. Fellers, and M. W. Davidson. Darkfield Illumination. [Online] Nikon Microscopy U. Available at: https://www.microscopyu.com/techniques/stereomicroscopy/darkfield-illumination

Beneath the opening, the surface should be a matt black. In-built illuminators must be switched off and replaced with a high-intensity light source such as a laser. Pointing this source to the specimen at an angle from the top or side through a glass dish or jar will generate the desired dark-field effect.

From my personal experience, these are some of the distinct advantages and ultimately disadvantages of projector sewing:

Rijal, N. (2021) Dark-field Microscopy: Principle and Uses. [Online] Microbe Online. Available at: https://microbeonline.com/dark-field-microscopy/

There is a lot of factors to take into account when deciding on a projector, I highly recommend joining the Facebook group; Projectors for Sewing. This group is a wealth of knowledge, they have checklists and advice on what might suit your situation the best.

Using a projector in sewing is an emerging trend, bringing sewing and patterns into the digital age. This exciting use of existing technology holds so much promise for sewing enthusiasts.

As a high-contrast microscopy technique, dark-field microscopy is a cheaper alternative to more advanced phase-contrast optics developed in the 1940s by Dutch scientist Frits Zernike. Today, inexpensive dark field microscopy instrumentation delivers better contrast and resolution than student-grade phase-contrast equipment is capable of.

HAADF-STEM

Dark-field microscopy has been used since the early 20th century to observe living, unstained cells and microorganisms. Specimens are brightly lit against a dark background to provide the contrast needed to study samples in solutions or natural aquatic environments such as pond water. This article looks at what dark-field microscopy is and its applications.

In a nutshell, Ultra Short Throws (or UST’s) are being utilised as a more portable option. Ceiling mounted is better for those who have a designated cutting area.

The microscope operator focuses at low power, then places a slide with occulting discs between the light source and the condenser in the light’s path. The slide should be brought as close as possible to the bottom of the condenser.

Dark-field microscopes were extremely popular in the first half of the 20th century, and many researchers focused on optimizing condenser systems and illuminators to make the technique as effective as possible. However, the introduction of phase-contrast, differential contrast, and Hoffman modulation contrast from the middle of the 20th century has caused dark-field techniques to fade from view.

Specimens are placed on the microscope stage to obtain a dark field optical image. The illumination must be as uniform as possible, and aperture diaphragm available in the condenser needs to be opened as wide as possible.

Dark fieldscattering spectroscopy

Dark-field microscopy is slightly more complicated in stereomicroscopy. A specialized stand that has a reflection mirror and a plate to shield light is required. This directs an inverted hollow cone of light toward the specimen at the correct oblique angles for a dark-field effect. Complex condenser systems with multiple lenses, or condensers with internal mirrors that reflect surfaces at specific geometries, are used in high-end stereo microscopes for dark-field microscopy.

Con’s:– Modifications of pattern pieces is more challenging, but not impossible– Can not lay pattern pieces ‘jigsaw’ style to get the most from fabric. You need to plan a lot of that virtually– If you don’t have a dedicated sewing area, there are a couple more steps each time to set up your projector

Lightfieldmicroscopy

Reuven Silverman of Ophir discusses the critical role of M2 measurements in laser technology for optimization and quality control in various industries.

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Fluorescence microscope

I definitely feel this is a hugely positive step in pattern making and designing, I am excited to be at the forefront of this exciting new development.

Although more sophisticated high-contrast microscopy methods have been developed, dark-field microscopy is effective in some instances. It is a beneficial tool for studying biological and medical phenomena that cannot be easily separated from their immediate surroundings.

Keeping light out of the objective reveals the light that was scattered by samples on the slide itself. Instead of coming through the specimen and into the objective as is the case in bright field microscopy, light that is reflected by particles on the slide makes it to the observer.

Pilkington, Ben. "What are Dark-Field Microscopes?". AZoOptics. 17 December 2024. .

Ben Pilkington is a freelance writer who is interested in society and technology. He enjoys learning how the latest scientific developments can affect us and imagining what will be possible in the future. Since completing graduate studies at Oxford University in 2016, Ben has reported on developments in computer software, the UK technology industry, digital rights and privacy, industrial automation, IoT, AI, additive manufacturing, sustainability, and clean technology.

Enrol in our Conquer Stretch Fabric Sewing Course before 15th April 2024 and you can join our first ever Sewing Bootcamp! Be guided through 4 stretch sewing modules with weekly calls and exclusive online sewing community.

By using a projector, you eliminate the very lengthy and cumbersome steps of having to print your A4 pages from PDF patterns and assembling them together, or even with traditional paper patterns, having to trace and cut the size you need.

Pilkington, Ben. "What are Dark-Field Microscopes?". AZoOptics. https://www.azooptics.com/Article.aspx?ArticleID=2125. (accessed December 17, 2024).

Dark-field microscopes are optical microscopes with an extra non-transparent disc placed beneath the condenser lens or a specially designed condenser lens that has a central area blacked out. With either technique, light from the source cannot directly enter the microscope’s objective.

But there is still interest in developing and optimizing dark field microscopy techniques. Transmitted dark-field microscopy has recently received renewed interest as it can be used in combination with fluorescence microscopy. It is expected that newer high-contrast techniques, such as the oblique coherent contrast method developed by Nikon, will eventually displace dark field microscopy in research and industry settings.

A very important question. I was able to pick up my projector second hand from a school for $250AUD. It is an Epson EB-595Wi UST, I know a number of people who have bought their projector second hand as well. It is worth keeping your eye on eBay and Facebook marketplace for any deals. Otherwise a brand new ceiling mount projector is approximately around the $200-$300AUD mark for a reasonable one, while the UST’s can be around the $2k-$3k AUD price bracket.

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Projector sewing is using a common household or office projector to project your pattern pieces onto a flat surface. Place your fabric down on the surface, use your rotary cutter to cut out the pieces you need.

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Pilkington, Ben. 2022. What are Dark-Field Microscopes?. AZoOptics, viewed 17 December 2024, https://www.azooptics.com/Article.aspx?ArticleID=2125.

A big incentive for me is the fact you don’t then have many ten’s or indeed hundreds of patterns and sizes lying around trying to store them. All you need is data storage, either on your computer or online, a place for your cutting mat and projector itself (if you don’t have a ceiling mounted model). Most Ultra Short Throws are around the size of a large shoe box.

Phase contrast

Since becoming more adept at using my projector, I have been soooo much more adventurous in my sewing. I have been confident to use more of my fabric stash, as I don’t have the challenge of all the prep work in trying new patterns to hold me back. What previously might have taken me a whole night to print, stick, trace and cut to try one new pattern, now takes me no time and I have been known to cut out 2 or 3 patterns in one night ready to sew up the following day. Or sometimes, the same night! It is just SO MUCH quicker.

As projector sewing becomes more popular, I have no doubt we will start to see projectors emerge that are targeted to the sewing world specifically. With the development of this technology, it may help overcome some of the challenges with the current set up. A lot of pattern designers are already offering pdf print as well as projector files, A0 or copy shop files are generally also able to be used successfully as well.

Caprette, D. R. (2012) Dark Field Viewing. [Online] Rice University. Available at: https://www.ruf.rice.edu/~bioslabs/methods/microscopy/dfield.html

Do you hate printing, sticking, tracing, cutting, pinning then cutting again on your PDF patterns only to realise the size doesn’t fit? Or you blinked and your kid is in the next size so you have to trace and cut a new size?

Dark-field effects can be obtained with relatively basic optical microscopy equipment, modified with an occulting disc. A reliable optical microscope can be modified to reflect light toward the viewer rather than pass directly through the sample to the viewer, particularly at low magnification (up to 100x). However, specialist dark field instrumentation with occulting discs that are built into the condenser itself yield much more dramatic dark-field imagery.